diff --git a/tests/snippets/builtin_complex.py b/tests/snippets/builtin_complex.py
index 2df8e4df7..4d0fa1202 100644
--- a/tests/snippets/builtin_complex.py
+++ b/tests/snippets/builtin_complex.py
@@ -24,6 +24,11 @@ assert complex(1, 2) != complex(1, 1)
 assert complex(1, 2) != 'foo'
 assert complex(1, 2).__eq__('foo') == NotImplemented
 
+# __mul__
+
+assert complex(2, -3) * complex(-5, 7) == complex(11, 29)
+assert complex(2, -3) * 5 == complex(10, -15)
+
 # __neg__
 
 assert -complex(1, -1) == complex(-1, 1)
diff --git a/tests/snippets/builtin_range.py b/tests/snippets/builtin_range.py
index 2ea71f7a7..55d4f5194 100644
--- a/tests/snippets/builtin_range.py
+++ b/tests/snippets/builtin_range.py
@@ -27,6 +27,11 @@ assert range(4, 10, 2).count(4) == 1
 assert range(4, 10, 2).count(7) == 0
 assert range(10).count("foo") == 0
 
+# __eq__
+assert range(1, 2, 3) == range(1, 2, 3)
+assert range(1, 2, 1) == range(1, 2)
+assert range(2) == range(0, 2)
+
 # __bool__
 assert bool(range(1))
 assert bool(range(1, 2))
@@ -54,3 +59,9 @@ assert list(reversed(range(1,10,5))) == [6, 1]
 # range retains the original int refs
 i = 2**64
 assert range(i).stop is i
+
+# negative index
+assert range(10)[-1] == 9
+assert_raises(IndexError, lambda: range(10)[-11], 'out of bound')
+assert range(10)[-2:4] == range(8, 4)
+assert range(10)[-6:-2] == range(4, 8)
diff --git a/tests/snippets/bytearray.py b/tests/snippets/bytearray.py
index 563da2c53..4286f8171 100644
--- a/tests/snippets/bytearray.py
+++ b/tests/snippets/bytearray.py
@@ -65,3 +65,9 @@ except IndexError:
     pass
 else:
     assert False
+
+a = bytearray(b'appen')
+assert len(a) == 5
+a.append(100)
+assert len(a) == 6
+assert a.pop() == 100
diff --git a/tests/snippets/floats.py b/tests/snippets/floats.py
index 176ce927e..788c52195 100644
--- a/tests/snippets/floats.py
+++ b/tests/snippets/floats.py
@@ -8,6 +8,7 @@ a = 1.2
 b = 1.3
 c = 1.2
 z = 2
+ov = 10 ** 1000
 
 assert -a == -1.2
 
@@ -37,6 +38,20 @@ assert a / z == 0.6
 assert 6 / a == 5.0
 assert 2.0 % z == 0.0
 assert z % 2.0 == 0.0
+assert_raises(OverflowError, lambda: a + ov)
+assert_raises(OverflowError, lambda: a - ov)
+assert_raises(OverflowError, lambda: a * ov)
+assert_raises(OverflowError, lambda: a / ov)
+assert_raises(OverflowError, lambda: a // ov)
+assert_raises(OverflowError, lambda: a % ov)
+assert_raises(OverflowError, lambda: a ** ov)
+assert_raises(OverflowError, lambda: ov + a)
+assert_raises(OverflowError, lambda: ov - a)
+assert_raises(OverflowError, lambda: ov * a)
+assert_raises(OverflowError, lambda: ov / a)
+assert_raises(OverflowError, lambda: ov // a)
+assert_raises(OverflowError, lambda: ov % a)
+# assert_raises(OverflowError, lambda: ov ** a)
 
 assert a < 5
 assert a <= 5
@@ -91,6 +106,8 @@ assert 2.0.__sub__(1.0) == 1.0
 assert 2.0.__rmul__(1.0) == 2.0
 assert 1.0.__truediv__(2.0) == 0.5
 assert 1.0.__rtruediv__(2.0) == 2.0
+assert 2.5.__divmod__(2.0) == (1.0, 0.5)
+assert 2.0.__rdivmod__(2.5) == (1.0, 0.5)
 
 assert 1.0.__add__(1) == 2.0
 assert 1.0.__radd__(1) == 2.0
@@ -105,6 +122,11 @@ assert 2.0.__rmod__(2) == 0.0
 assert_raises(ZeroDivisionError, lambda: 2.0 / 0)
 assert_raises(ZeroDivisionError, lambda: 2.0 // 0)
 assert_raises(ZeroDivisionError, lambda: 2.0 % 0)
+assert_raises(ZeroDivisionError, lambda: divmod(2.0, 0))
+assert_raises(ZeroDivisionError, lambda: 2 / 0.0)
+assert_raises(ZeroDivisionError, lambda: 2 // 0.0)
+assert_raises(ZeroDivisionError, lambda: 2 % 0.0)
+# assert_raises(ZeroDivisionError, lambda: divmod(2, 0.0))
 
 assert 1.2.__int__() == 1
 assert 1.2.__float__() == 1.2
@@ -123,6 +145,10 @@ assert 1.5.__round__(None) == 2.0
 assert_raises(OverflowError, float('inf').__round__)
 assert_raises(ValueError, float('nan').__round__)
 
+assert 1.2 ** 2 == 1.44
+assert_raises(OverflowError, lambda: 1.2 ** (10 ** 1000))
+assert 3 ** 2.0 == 9.0
+
 assert (1.7).real == 1.7
 assert (1.3).is_integer() == False
 assert (1.0).is_integer()    == True
diff --git a/tests/snippets/ints.py b/tests/snippets/ints.py
index 1fbbc2bef..a072cc542 100644
--- a/tests/snippets/ints.py
+++ b/tests/snippets/ints.py
@@ -74,3 +74,37 @@ with assertRaises(TypeError):
 with assertRaises(TypeError):
     # check that first parameter is truly positional only
     int(val_options=1)
+
+class A(object):
+    def __int__(self):
+        return 10
+
+assert int(A()) == 10
+
+class B(object):
+    pass
+
+b = B()
+b.__int__ = lambda: 20
+
+with assertRaises(TypeError):
+    assert int(b) == 20
+
+class C(object):
+    def __int__(self):
+        return 'str'
+
+with assertRaises(TypeError):
+    int(C())
+
+class I(int):
+    def __int__(self):
+        return 3
+
+assert int(I(1)) == 3
+
+class F(float):
+    def __int__(self):
+        return 3
+
+assert int(F(1.2)) == 3
diff --git a/tests/snippets/testutils.py b/tests/snippets/testutils.py
index 7dda57b17..49b7fedc1 100644
--- a/tests/snippets/testutils.py
+++ b/tests/snippets/testutils.py
@@ -14,9 +14,9 @@ def assert_raises(exc_type, expr, msg=None):
     except exc_type:
         pass
     else:
-        failmsg = '{!s} was not raised'.format(exc_type.__name__)
+        failmsg = '{} was not raised'.format(exc_type.__name__)
         if msg is not None:
-            failmsg += ': {!s}'.format(msg)
+            failmsg += ': {}'.format(msg)
         assert False, failmsg
 
 
@@ -29,8 +29,8 @@ class assertRaises:
 
     def __exit__(self, exc_type, exc_val, exc_tb):
         if exc_type is None:
-            failmsg = '{!s} was not raised'.format(self.expected.__name__)
-            assert False, failmsg            
+            failmsg = '{} was not raised'.format(self.expected.__name__)
+            assert False, failmsg
         if not issubclass(exc_type, self.expected):
             return False
         return True
diff --git a/vm/src/builtins.rs b/vm/src/builtins.rs
index 41082707e..300d11b31 100644
--- a/vm/src/builtins.rs
+++ b/vm/src/builtins.rs
@@ -123,11 +123,14 @@ fn builtin_dir(vm: &VirtualMachine, args: PyFuncArgs) -> PyResult {
 }
 
 fn builtin_divmod(vm: &VirtualMachine, args: PyFuncArgs) -> PyResult {
-    arg_check!(vm, args, required = [(x, None), (y, None)]);
-    match vm.get_method(x.clone(), "__divmod__") {
-        Ok(attrib) => vm.invoke(attrib, vec![y.clone()]),
-        Err(..) => Err(vm.new_type_error("unsupported operand type(s) for divmod".to_string())),
-    }
+    arg_check!(vm, args, required = [(a, None), (b, None)]);
+    vm.call_or_reflection(
+        a.clone(),
+        b.clone(),
+        "__divmod__",
+        "__rdivmod__",
+        |vm, a, b| Err(vm.new_unsupported_operand_error(a, b, "divmod")),
+    )
 }
 
 /// Implements `eval`.
diff --git a/vm/src/obj/objbytearray.rs b/vm/src/obj/objbytearray.rs
index f6244399b..6f78ecf48 100644
--- a/vm/src/obj/objbytearray.rs
+++ b/vm/src/obj/objbytearray.rs
@@ -7,7 +7,7 @@ use std::ops::{Deref, DerefMut};
 use num_traits::ToPrimitive;
 
 use crate::function::OptionalArg;
-use crate::pyobject::{PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::VirtualMachine;
 
 use super::objint;
@@ -79,15 +79,12 @@ pub fn init(context: &PyContext) {
         "istitle" =>context.new_rustfunc(PyByteArrayRef::istitle),
         "isupper" => context.new_rustfunc(PyByteArrayRef::isupper),
         "lower" => context.new_rustfunc(PyByteArrayRef::lower),
+        "append" => context.new_rustfunc(PyByteArrayRef::append),
         "pop" => context.new_rustfunc(PyByteArrayRef::pop),
         "upper" => context.new_rustfunc(PyByteArrayRef::upper)
     });
 
-    let bytearrayiterator_type = &context.bytearrayiterator_type;
-    extend_class!(context, bytearrayiterator_type, {
-        "__next__" => context.new_rustfunc(PyByteArrayIteratorRef::next),
-        "__iter__" => context.new_rustfunc(PyByteArrayIteratorRef::iter),
-    });
+    PyByteArrayIterator::extend_class(context, &context.bytearrayiterator_type);
 }
 
 fn bytearray_new(
@@ -213,6 +210,10 @@ impl PyByteArrayRef {
         self.value.borrow_mut().clear();
     }
 
+    fn append(self, x: u8, _vm: &VirtualMachine) {
+        self.value.borrow_mut().push(x);
+    }
+
     fn pop(self, vm: &VirtualMachine) -> PyResult<u8> {
         let mut bytes = self.value.borrow_mut();
         bytes
@@ -282,6 +283,7 @@ mod tests {
     }
 }
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PyByteArrayIterator {
     position: Cell<usize>,
@@ -294,10 +296,10 @@ impl PyValue for PyByteArrayIterator {
     }
 }
 
-type PyByteArrayIteratorRef = PyRef<PyByteArrayIterator>;
-
-impl PyByteArrayIteratorRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult<u8> {
+#[pyimpl]
+impl PyByteArrayIterator {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult<u8> {
         if self.position.get() < self.bytearray.value.borrow().len() {
             let ret = self.bytearray.value.borrow()[self.position.get()];
             self.position.set(self.position.get() + 1);
@@ -307,7 +309,8 @@ impl PyByteArrayIteratorRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
diff --git a/vm/src/obj/objbytes.rs b/vm/src/obj/objbytes.rs
index 0556de053..df9795902 100644
--- a/vm/src/obj/objbytes.rs
+++ b/vm/src/obj/objbytes.rs
@@ -64,11 +64,7 @@ pub fn init(context: &PyContext) {
     extend_class!(context, bytes_type, {
     "fromhex" => context.new_rustfunc(PyBytesRef::fromhex),
     });
-    let bytesiterator_type = &context.bytesiterator_type;
-    extend_class!(context, bytesiterator_type, {
-    "__next__" => context.new_rustfunc(PyBytesIteratorRef::next),
-    "__iter__" => context.new_rustfunc(PyBytesIteratorRef::iter),
-    });
+    PyBytesIterator::extend_class(context, &context.bytesiterator_type);
 }
 
 #[pyimpl]
@@ -271,6 +267,7 @@ impl PyBytesRef {
     }
 }
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PyBytesIterator {
     position: Cell<usize>,
@@ -283,10 +280,10 @@ impl PyValue for PyBytesIterator {
     }
 }
 
-type PyBytesIteratorRef = PyRef<PyBytesIterator>;
-
-impl PyBytesIteratorRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult<u8> {
+#[pyimpl]
+impl PyBytesIterator {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult<u8> {
         if self.position.get() < self.bytes.inner.len() {
             let ret = self.bytes[self.position.get()];
             self.position.set(self.position.get() + 1);
@@ -296,7 +293,8 @@ impl PyBytesIteratorRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
diff --git a/vm/src/obj/objcomplex.rs b/vm/src/obj/objcomplex.rs
index 93a0559aa..f9ff9d9b0 100644
--- a/vm/src/obj/objcomplex.rs
+++ b/vm/src/obj/objcomplex.rs
@@ -67,7 +67,9 @@ impl PyComplexRef {
 }
 
 fn to_complex(value: PyObjectRef, vm: &VirtualMachine) -> PyResult<Option<Complex64>> {
-    if objtype::isinstance(&value, &vm.ctx.int_type()) {
+    if objtype::isinstance(&value, &vm.ctx.complex_type()) {
+        Ok(Some(get_value(&value)))
+    } else if objtype::isinstance(&value, &vm.ctx.int_type()) {
         match objint::get_value(&value).to_f64() {
             Some(v) => Ok(Some(Complex64::new(v, 0.0))),
             None => Err(vm.new_overflow_error("int too large to convert to float".to_string())),
@@ -161,6 +163,28 @@ impl PyComplex {
         vm.ctx.new_bool(result)
     }
 
+    #[pymethod(name = "__float__")]
+    fn float(&self, vm: &VirtualMachine) -> PyResult {
+        return Err(vm.new_type_error(String::from("Can't convert complex to float")));
+    }
+
+    #[pymethod(name = "__int__")]
+    fn int(&self, vm: &VirtualMachine) -> PyResult {
+        return Err(vm.new_type_error(String::from("Can't convert complex to int")));
+    }
+
+    #[pymethod(name = "__mul__")]
+    fn mul(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+        match to_complex(other, vm) {
+            Ok(Some(other)) => Ok(vm.ctx.new_complex(Complex64::new(
+                self.value.re * other.re - self.value.im * other.im,
+                self.value.re * other.im + self.value.im * other.re,
+            ))),
+            Ok(None) => Ok(vm.ctx.not_implemented()),
+            Err(err) => Err(err),
+        }
+    }
+
     #[pymethod(name = "__neg__")]
     fn neg(&self, _vm: &VirtualMachine) -> PyComplex {
         PyComplex::from(-self.value)
diff --git a/vm/src/obj/objenumerate.rs b/vm/src/obj/objenumerate.rs
index c94aeabbd..56d232272 100644
--- a/vm/src/obj/objenumerate.rs
+++ b/vm/src/obj/objenumerate.rs
@@ -5,13 +5,14 @@ use num_bigint::BigInt;
 use num_traits::Zero;
 
 use crate::function::OptionalArg;
-use crate::pyobject::{PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::VirtualMachine;
 
 use super::objint::PyIntRef;
 use super::objiter;
 use super::objtype::PyClassRef;
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PyEnumerate {
     counter: RefCell<BigInt>,
@@ -44,8 +45,10 @@ fn enumerate_new(
     .into_ref_with_type(vm, cls)
 }
 
-impl PyEnumerateRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult {
+#[pyimpl]
+impl PyEnumerate {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult {
         let iterator = &self.iterator;
         let counter = &self.counter;
         let next_obj = objiter::call_next(vm, iterator)?;
@@ -58,16 +61,15 @@ impl PyEnumerateRef {
         Ok(result)
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
 pub fn init(context: &PyContext) {
-    let enumerate_type = &context.enumerate_type;
-    extend_class!(context, enumerate_type, {
+    PyEnumerate::extend_class(context, &context.enumerate_type);
+    extend_class!(context, &context.enumerate_type, {
         "__new__" => context.new_rustfunc(enumerate_new),
-        "__next__" => context.new_rustfunc(PyEnumerateRef::next),
-        "__iter__" => context.new_rustfunc(PyEnumerateRef::iter),
     });
 }
diff --git a/vm/src/obj/objfilter.rs b/vm/src/obj/objfilter.rs
index 858a0531a..24800d6aa 100644
--- a/vm/src/obj/objfilter.rs
+++ b/vm/src/obj/objfilter.rs
@@ -1,4 +1,4 @@
-use crate::pyobject::{IdProtocol, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{IdProtocol, PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::VirtualMachine; // Required for arg_check! to use isinstance
 
 use super::objbool;
@@ -7,6 +7,11 @@ use crate::obj::objtype::PyClassRef;
 
 pub type PyFilterRef = PyRef<PyFilter>;
 
+/// filter(function or None, iterable) --> filter object
+///
+/// Return an iterator yielding those items of iterable for which function(item)
+/// is true. If function is None, return the items that are true.
+#[pyclass]
 #[derive(Debug)]
 pub struct PyFilter {
     predicate: PyObjectRef,
@@ -34,8 +39,10 @@ fn filter_new(
     .into_ref_with_type(vm, cls)
 }
 
-impl PyFilterRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult {
+#[pyimpl]
+impl PyFilter {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult {
         let predicate = &self.predicate;
         let iterator = &self.iterator;
         loop {
@@ -53,23 +60,15 @@ impl PyFilterRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
 pub fn init(context: &PyContext) {
-    let filter_type = &context.filter_type;
-
-    let filter_doc =
-        "filter(function or None, iterable) --> filter object\n\n\
-         Return an iterator yielding those items of iterable for which function(item)\n\
-         is true. If function is None, return the items that are true.";
-
-    extend_class!(context, filter_type, {
+    PyFilter::extend_class(context, &context.filter_type);
+    extend_class!(context, &context.filter_type, {
         "__new__" => context.new_rustfunc(filter_new),
-        "__doc__" => context.new_str(filter_doc.to_string()),
-        "__next__" => context.new_rustfunc(PyFilterRef::next),
-        "__iter__" => context.new_rustfunc(PyFilterRef::iter),
     });
 }
diff --git a/vm/src/obj/objfloat.rs b/vm/src/obj/objfloat.rs
index 42810da8e..6c097b706 100644
--- a/vm/src/obj/objfloat.rs
+++ b/vm/src/obj/objfloat.rs
@@ -43,9 +43,27 @@ impl From<f64> for PyFloat {
     }
 }
 
-fn mod_(v1: f64, v2: f64, vm: &VirtualMachine) -> PyResult {
+fn try_float(value: &PyObjectRef, vm: &VirtualMachine) -> PyResult<Option<f64>> {
+    Ok(if objtype::isinstance(&value, &vm.ctx.float_type()) {
+        Some(get_value(&value))
+    } else if objtype::isinstance(&value, &vm.ctx.int_type()) {
+        Some(objint::get_float_value(&value, vm)?)
+    } else {
+        None
+    })
+}
+
+fn inner_div(v1: f64, v2: f64, vm: &VirtualMachine) -> PyResult<f64> {
     if v2 != 0.0 {
-        Ok(vm.ctx.new_float(v1 % v2))
+        Ok(v1 / v2)
+    } else {
+        Err(vm.new_zero_division_error("float division by zero".to_string()))
+    }
+}
+
+fn inner_mod(v1: f64, v2: f64, vm: &VirtualMachine) -> PyResult<f64> {
+    if v2 != 0.0 {
+        Ok(v1 % v2)
     } else {
         Err(vm.new_zero_division_error("float mod by zero".to_string()))
     }
@@ -73,6 +91,22 @@ fn try_to_bigint(value: f64, vm: &VirtualMachine) -> PyResult<BigInt> {
     }
 }
 
+fn inner_floordiv(v1: f64, v2: f64, vm: &VirtualMachine) -> PyResult<f64> {
+    if v2 != 0.0 {
+        Ok((v1 / v2).floor())
+    } else {
+        Err(vm.new_zero_division_error("float floordiv by zero".to_string()))
+    }
+}
+
+fn inner_divmod(v1: f64, v2: f64, vm: &VirtualMachine) -> PyResult<(f64, f64)> {
+    if v2 != 0.0 {
+        Ok(((v1 / v2).floor(), v1 % v2))
+    } else {
+        Err(vm.new_zero_division_error("float divmod()".to_string()))
+    }
+}
+
 #[pyimpl]
 impl PyFloat {
     #[pymethod(name = "__eq__")]
@@ -153,20 +187,15 @@ impl PyFloat {
     }
 
     #[pymethod(name = "__add__")]
-    fn add(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyObjectRef {
-        let v1 = self.value;
-        if objtype::isinstance(&other, &vm.ctx.float_type()) {
-            vm.ctx.new_float(v1 + get_value(&other))
-        } else if objtype::isinstance(&other, &vm.ctx.int_type()) {
-            vm.ctx
-                .new_float(v1 + objint::get_value(&other).to_f64().unwrap())
-        } else {
-            vm.ctx.not_implemented()
-        }
+    fn add(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| (self.value + other).into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__radd__")]
-    fn radd(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyObjectRef {
+    fn radd(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
         self.add(other, vm)
     }
 
@@ -177,45 +206,51 @@ impl PyFloat {
 
     #[pymethod(name = "__divmod__")]
     fn divmod(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        if objtype::isinstance(&other, &vm.ctx.float_type())
-            || objtype::isinstance(&other, &vm.ctx.int_type())
-        {
-            let r1 = self.floordiv(other.clone(), vm)?;
-            let r2 = self.mod_(other, vm)?;
-            Ok(vm.ctx.new_tuple(vec![r1, r2]))
-        } else {
-            Ok(vm.ctx.not_implemented())
-        }
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| {
+                let (r1, r2) = inner_divmod(self.value, other, vm)?;
+                Ok(vm
+                    .ctx
+                    .new_tuple(vec![vm.ctx.new_float(r1), vm.ctx.new_float(r2)]))
+            },
+        )
+    }
+
+    #[pymethod(name = "__rdivmod__")]
+    fn rdivmod(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| {
+                let (r1, r2) = inner_divmod(other, self.value, vm)?;
+                Ok(vm
+                    .ctx
+                    .new_tuple(vec![vm.ctx.new_float(r1), vm.ctx.new_float(r2)]))
+            },
+        )
     }
 
     #[pymethod(name = "__floordiv__")]
     fn floordiv(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        let v1 = self.value;
-        let v2 = if objtype::isinstance(&other, &vm.ctx.float_type) {
-            get_value(&other)
-        } else if objtype::isinstance(&other, &vm.ctx.int_type) {
-            objint::get_float_value(&other, vm)?
-        } else {
-            return Ok(vm.ctx.not_implemented());
-        };
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| inner_floordiv(self.value, other, vm)?.into_pyobject(vm),
+        )
+    }
 
-        if v2 != 0.0 {
-            Ok(vm.ctx.new_float((v1 / v2).floor()))
-        } else {
-            Err(vm.new_zero_division_error("float floordiv by zero".to_string()))
-        }
+    #[pymethod(name = "__rfloordiv__")]
+    fn rfloordiv(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| inner_floordiv(other, self.value, vm)?.into_pyobject(vm),
+        )
     }
 
     fn new_float(cls: PyClassRef, arg: PyObjectRef, vm: &VirtualMachine) -> PyResult<PyFloatRef> {
         let value = if objtype::isinstance(&arg, &vm.ctx.float_type()) {
             get_value(&arg)
         } else if objtype::isinstance(&arg, &vm.ctx.int_type()) {
-            match objint::get_float_value(&arg, vm) {
-                Ok(f) => f,
-                Err(e) => {
-                    return Err(e);
-                }
-            }
+            objint::get_float_value(&arg, vm)?
         } else if objtype::isinstance(&arg, &vm.ctx.str_type()) {
             match lexical::try_parse(objstr::get_value(&arg)) {
                 Ok(f) => f,
@@ -246,28 +281,18 @@ impl PyFloat {
 
     #[pymethod(name = "__mod__")]
     fn mod_(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        let v1 = self.value;
-        let v2 = if objtype::isinstance(&other, &vm.ctx.float_type) {
-            get_value(&other)
-        } else if objtype::isinstance(&other, &vm.ctx.int_type) {
-            objint::get_float_value(&other, vm)?
-        } else {
-            return Ok(vm.ctx.not_implemented());
-        };
-
-        mod_(v1, v2, vm)
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| inner_mod(self.value, other, vm)?.into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__rmod__")]
     fn rmod(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        let v2 = self.value;
-        let v1 = if objtype::isinstance(&other, &vm.ctx.int_type) {
-            objint::get_float_value(&other, vm)?
-        } else {
-            return Ok(vm.ctx.not_implemented());
-        };
-
-        mod_(v1, v2, vm)
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| inner_mod(other, self.value, vm)?.into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__neg__")]
@@ -276,44 +301,35 @@ impl PyFloat {
     }
 
     #[pymethod(name = "__pow__")]
-    fn pow(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyObjectRef {
-        let v1 = self.value;
-        if objtype::isinstance(&other, &vm.ctx.float_type()) {
-            vm.ctx.new_float(v1.powf(get_value(&other)))
-        } else if objtype::isinstance(&other, &vm.ctx.int_type()) {
-            let result = v1.powf(objint::get_value(&other).to_f64().unwrap());
-            vm.ctx.new_float(result)
-        } else {
-            vm.ctx.not_implemented()
-        }
+    fn pow(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| self.value.powf(other).into_pyobject(vm),
+        )
+    }
+
+    #[pymethod(name = "__rpow__")]
+    fn rpow(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| other.powf(self.value).into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__sub__")]
     fn sub(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        let v1 = self.value;
-        if objtype::isinstance(&other, &vm.ctx.float_type()) {
-            Ok(vm.ctx.new_float(v1 - get_value(&other)))
-        } else if objtype::isinstance(&other, &vm.ctx.int_type()) {
-            Ok(vm
-                .ctx
-                .new_float(v1 - objint::get_value(&other).to_f64().unwrap()))
-        } else {
-            Ok(vm.ctx.not_implemented())
-        }
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| (self.value - other).into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__rsub__")]
     fn rsub(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        let v1 = self.value;
-        if objtype::isinstance(&other, &vm.ctx.float_type()) {
-            Ok(vm.ctx.new_float(get_value(&other) - v1))
-        } else if objtype::isinstance(&other, &vm.ctx.int_type()) {
-            Ok(vm
-                .ctx
-                .new_float(objint::get_value(&other).to_f64().unwrap() - v1))
-        } else {
-            Ok(vm.ctx.not_implemented())
-        }
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| (other - self.value).into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__repr__")]
@@ -323,52 +339,26 @@ impl PyFloat {
 
     #[pymethod(name = "__truediv__")]
     fn truediv(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        let v1 = self.value;
-        let v2 = if objtype::isinstance(&other, &vm.ctx.float_type) {
-            get_value(&other)
-        } else if objtype::isinstance(&other, &vm.ctx.int_type) {
-            objint::get_float_value(&other, vm)?
-        } else {
-            return Ok(vm.ctx.not_implemented());
-        };
-
-        if v2 != 0.0 {
-            Ok(vm.ctx.new_float(v1 / v2))
-        } else {
-            Err(vm.new_zero_division_error("float division by zero".to_string()))
-        }
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| inner_div(self.value, other, vm)?.into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__rtruediv__")]
     fn rtruediv(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        let v1 = self.value;
-        let v2 = if objtype::isinstance(&other, &vm.ctx.float_type) {
-            get_value(&other)
-        } else if objtype::isinstance(&other, &vm.ctx.int_type) {
-            objint::get_float_value(&other, vm)?
-        } else {
-            return Ok(vm.ctx.not_implemented());
-        };
-
-        if v1 != 0.0 {
-            Ok(vm.ctx.new_float(v2 / v1))
-        } else {
-            Err(vm.new_zero_division_error("float division by zero".to_string()))
-        }
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| inner_div(other, self.value, vm)?.into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__mul__")]
     fn mul(&self, other: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        let v1 = self.value;
-        if objtype::isinstance(&other, &vm.ctx.float_type) {
-            Ok(vm.ctx.new_float(v1 * get_value(&other)))
-        } else if objtype::isinstance(&other, &vm.ctx.int_type) {
-            Ok(vm
-                .ctx
-                .new_float(v1 * objint::get_value(&other).to_f64().unwrap()))
-        } else {
-            Ok(vm.ctx.not_implemented())
-        }
+        try_float(&other, vm)?.map_or_else(
+            || Ok(vm.ctx.not_implemented()),
+            |other| (self.value * other).into_pyobject(vm),
+        )
     }
 
     #[pymethod(name = "__rmul__")]
diff --git a/vm/src/obj/objint.rs b/vm/src/obj/objint.rs
index c9a5c9a40..3687ed2b0 100644
--- a/vm/src/obj/objint.rs
+++ b/vm/src/obj/objint.rs
@@ -1,12 +1,12 @@
 use std::fmt;
 use std::hash::{Hash, Hasher};
 
-use num_bigint::{BigInt, ToBigInt};
+use num_bigint::BigInt;
 use num_integer::Integer;
 use num_traits::{Pow, Signed, ToPrimitive, Zero};
 
 use crate::format::FormatSpec;
-use crate::function::OptionalArg;
+use crate::function::{OptionalArg, PyFuncArgs};
 use crate::pyobject::{
     IntoPyObject, PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue, TryFromObject,
     TypeProtocol,
@@ -510,11 +510,8 @@ fn int_new(cls: PyClassRef, options: IntOptions, vm: &VirtualMachine) -> PyResul
 }
 
 // Casting function:
-// TODO: this should just call `__int__` on the object
 pub fn to_int(vm: &VirtualMachine, obj: &PyObjectRef, base: u32) -> PyResult<BigInt> {
     match_class!(obj.clone(),
-        i @ PyInt => Ok(i.as_bigint().clone()),
-        f @ PyFloat => Ok(f.to_f64().to_bigint().unwrap()),
         s @ PyString => {
             i32::from_str_radix(s.as_str(), base)
                 .map(BigInt::from)
@@ -523,10 +520,21 @@ pub fn to_int(vm: &VirtualMachine, obj: &PyObjectRef, base: u32) -> PyResult<Big
                     base, s
                 )))
         },
-        obj => Err(vm.new_type_error(format!(
-            "int() argument must be a string or a number, not '{}'",
-            obj.class().name
-        )))
+        obj => {
+            if let Ok(f) = vm.get_method(obj.clone(), "__int__") {
+                let int_res = vm.invoke(f, PyFuncArgs::default())?;
+                match int_res.payload::<PyInt>() {
+                    Some(i) => Ok(i.as_bigint().clone()),
+                    None => Err(vm.new_type_error(format!(
+                        "TypeError: __int__ returned non-int (type '{}')", int_res.class().name))),
+                }
+            } else {
+                Err(vm.new_type_error(format!(
+                    "int() argument must be a string or a number, not '{}'",
+                    obj.class().name
+                )))
+            }
+        }
     )
 }
 
diff --git a/vm/src/obj/objiter.rs b/vm/src/obj/objiter.rs
index 6e1dc1d06..efe672d62 100644
--- a/vm/src/obj/objiter.rs
+++ b/vm/src/obj/objiter.rs
@@ -4,7 +4,9 @@
 
 use std::cell::Cell;
 
-use crate::pyobject::{PyContext, PyObjectRef, PyRef, PyResult, PyValue, TypeProtocol};
+use crate::pyobject::{
+    PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue, TypeProtocol,
+};
 use crate::vm::VirtualMachine;
 
 use super::objtype;
@@ -75,6 +77,7 @@ pub fn new_stop_iteration(vm: &VirtualMachine) -> PyObjectRef {
     vm.new_exception(stop_iteration_type, "End of iterator".to_string())
 }
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PySequenceIterator {
     pub position: Cell<usize>,
@@ -87,10 +90,10 @@ impl PyValue for PySequenceIterator {
     }
 }
 
-type PySequenceIteratorRef = PyRef<PySequenceIterator>;
-
-impl PySequenceIteratorRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult {
+#[pyimpl]
+impl PySequenceIterator {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult {
         let number = vm.ctx.new_int(self.position.get());
         match vm.call_method(&self.obj, "__getitem__", vec![number]) {
             Ok(val) => {
@@ -105,16 +108,12 @@ impl PySequenceIteratorRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
 pub fn init(context: &PyContext) {
-    let iter_type = &context.iter_type;
-
-    extend_class!(context, iter_type, {
-        "__next__" => context.new_rustfunc(PySequenceIteratorRef::next),
-        "__iter__" => context.new_rustfunc(PySequenceIteratorRef::iter),
-    });
+    PySequenceIterator::extend_class(context, &context.iter_type);
 }
diff --git a/vm/src/obj/objlist.rs b/vm/src/obj/objlist.rs
index 5c1bad5af..6b00b6828 100644
--- a/vm/src/obj/objlist.rs
+++ b/vm/src/obj/objlist.rs
@@ -8,7 +8,8 @@ use num_traits::{One, Signed, ToPrimitive, Zero};
 
 use crate::function::{OptionalArg, PyFuncArgs};
 use crate::pyobject::{
-    IdProtocol, PyContext, PyIterable, PyObjectRef, PyRef, PyResult, PyValue, TryFromObject,
+    IdProtocol, PyClassImpl, PyContext, PyIterable, PyObjectRef, PyRef, PyResult, PyValue,
+    TryFromObject,
 };
 use crate::vm::{ReprGuard, VirtualMachine};
 
@@ -776,6 +777,7 @@ fn list_sort(vm: &VirtualMachine, args: PyFuncArgs) -> PyResult {
     Ok(vm.get_none())
 }
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PyListIterator {
     pub position: Cell<usize>,
@@ -788,10 +790,10 @@ impl PyValue for PyListIterator {
     }
 }
 
-type PyListIteratorRef = PyRef<PyListIterator>;
-
-impl PyListIteratorRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult {
+#[pyimpl]
+impl PyListIterator {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult {
         if self.position.get() < self.list.elements.borrow().len() {
             let ret = self.list.elements.borrow()[self.position.get()].clone();
             self.position.set(self.position.get() + 1);
@@ -801,8 +803,9 @@ impl PyListIteratorRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
@@ -848,9 +851,5 @@ pub fn init(context: &PyContext) {
         "remove" => context.new_rustfunc(PyListRef::remove)
     });
 
-    let listiterator_type = &context.listiterator_type;
-    extend_class!(context, listiterator_type, {
-        "__next__" => context.new_rustfunc(PyListIteratorRef::next),
-        "__iter__" => context.new_rustfunc(PyListIteratorRef::iter),
-    });
+    PyListIterator::extend_class(context, &context.listiterator_type);
 }
diff --git a/vm/src/obj/objmap.rs b/vm/src/obj/objmap.rs
index 061f4179f..61fe67c0d 100644
--- a/vm/src/obj/objmap.rs
+++ b/vm/src/obj/objmap.rs
@@ -1,10 +1,15 @@
 use crate::function::Args;
-use crate::pyobject::{PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::VirtualMachine;
 
 use super::objiter;
 use super::objtype::PyClassRef;
 
+/// map(func, *iterables) --> map object
+///
+/// Make an iterator that computes the function using arguments from
+/// each of the iterables.  Stops when the shortest iterable is exhausted.
+#[pyclass]
 #[derive(Debug)]
 pub struct PyMap {
     mapper: PyObjectRef,
@@ -35,8 +40,10 @@ fn map_new(
     .into_ref_with_type(vm, cls.clone())
 }
 
-impl PyMapRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult {
+#[pyimpl]
+impl PyMap {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult {
         let next_objs = self
             .iterators
             .iter()
@@ -47,22 +54,15 @@ impl PyMapRef {
         vm.invoke(self.mapper.clone(), next_objs)
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
 pub fn init(context: &PyContext) {
-    let map_type = &context.map_type;
-
-    let map_doc = "map(func, *iterables) --> map object\n\n\
-                   Make an iterator that computes the function using arguments from\n\
-                   each of the iterables.  Stops when the shortest iterable is exhausted.";
-
-    extend_class!(context, map_type, {
+    PyMap::extend_class(context, &context.map_type);
+    extend_class!(context, &context.map_type, {
         "__new__" => context.new_rustfunc(map_new),
-        "__next__" => context.new_rustfunc(PyMapRef::next),
-        "__iter__" => context.new_rustfunc(PyMapRef::iter),
-        "__doc__" => context.new_str(map_doc.to_string())
     });
 }
diff --git a/vm/src/obj/objrange.rs b/vm/src/obj/objrange.rs
index 1a21a49ad..2a43579c5 100644
--- a/vm/src/obj/objrange.rs
+++ b/vm/src/obj/objrange.rs
@@ -1,5 +1,4 @@
 use std::cell::Cell;
-use std::ops::Mul;
 
 use num_bigint::{BigInt, Sign};
 use num_integer::Integer;
@@ -7,14 +6,14 @@ use num_traits::{One, Signed, Zero};
 
 use crate::function::{OptionalArg, PyFuncArgs};
 use crate::pyobject::{
-    PyContext, PyObjectRef, PyRef, PyResult, PyValue, TryFromObject, TypeProtocol,
+    PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue, TryFromObject, TypeProtocol,
 };
 use crate::vm::VirtualMachine;
 
 use super::objint::{PyInt, PyIntRef};
 use super::objiter;
 use super::objslice::{PySlice, PySliceRef};
-use super::objtype::PyClassRef;
+use super::objtype::{self, PyClassRef};
 
 #[derive(Debug, Clone)]
 pub struct PyRange {
@@ -65,15 +64,22 @@ impl PyRange {
     }
 
     #[inline]
-    pub fn get<'a, T>(&'a self, index: T) -> Option<BigInt>
-    where
-        &'a BigInt: Mul<T, Output = BigInt>,
-    {
+    pub fn get(&self, index: &BigInt) -> Option<BigInt> {
         let start = self.start.as_bigint();
         let stop = self.stop.as_bigint();
         let step = self.step.as_bigint();
 
-        let result = start + step * index;
+        let index = if index < &BigInt::zero() {
+            let index = stop + index;
+            if index < BigInt::zero() {
+                return None;
+            }
+            index
+        } else {
+            index.clone()
+        };
+
+        let result = start + step * &index;
 
         if (self.forward() && !self.is_empty() && &result < stop)
             || (!self.forward() && !self.is_empty() && &result > stop)
@@ -104,6 +110,7 @@ pub fn init(context: &PyContext) {
         "__bool__" => context.new_rustfunc(PyRange::bool),
         "__contains__" => context.new_rustfunc(PyRange::contains),
         "__doc__" => context.new_str(range_doc.to_string()),
+        "__eq__" => context.new_rustfunc(PyRange::eq),
         "__getitem__" => context.new_rustfunc(PyRange::getitem),
         "__iter__" => context.new_rustfunc(PyRange::iter),
         "__len__" => context.new_rustfunc(PyRange::len),
@@ -117,11 +124,7 @@ pub fn init(context: &PyContext) {
         "step" => context.new_property(PyRange::step),
     });
 
-    let rangeiterator_type = &context.rangeiterator_type;
-    extend_class!(context, rangeiterator_type, {
-        "__next__" => context.new_rustfunc(PyRangeIteratorRef::next),
-        "__iter__" => context.new_rustfunc(PyRangeIteratorRef::iter),
-    });
+    PyRangeIterator::extend_class(context, &context.rangeiterator_type);
 }
 
 type PyRangeRef = PyRef<PyRange>;
@@ -240,6 +243,17 @@ impl PyRange {
         }
     }
 
+    fn eq(&self, rhs: PyObjectRef, vm: &VirtualMachine) -> bool {
+        if objtype::isinstance(&rhs, &vm.ctx.range_type()) {
+            let rhs = get_value(&rhs);
+            self.start.as_bigint() == rhs.start.as_bigint()
+                && self.stop.as_bigint() == rhs.stop.as_bigint()
+                && self.step.as_bigint() == rhs.step.as_bigint()
+        } else {
+            false
+        }
+    }
+
     fn index(&self, needle: PyObjectRef, vm: &VirtualMachine) -> PyResult<PyInt> {
         if let Ok(int) = needle.downcast::<PyInt>() {
             match self.index_of(int.as_bigint()) {
@@ -274,7 +288,7 @@ impl PyRange {
             }
             RangeIndex::Slice(slice) => {
                 let new_start = if let Some(int) = slice.start_index(vm)? {
-                    if let Some(i) = self.get(int) {
+                    if let Some(i) = self.get(&int) {
                         PyInt::new(i).into_ref(vm)
                     } else {
                         self.start.clone()
@@ -284,7 +298,7 @@ impl PyRange {
                 };
 
                 let new_end = if let Some(int) = slice.stop_index(vm)? {
-                    if let Some(i) = self.get(int) {
+                    if let Some(i) = self.get(&int) {
                         PyInt::new(i).into_ref(vm)
                     } else {
                         self.stop.clone()
@@ -323,6 +337,7 @@ fn range_new(vm: &VirtualMachine, args: PyFuncArgs) -> PyResult {
     Ok(range.into_object())
 }
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PyRangeIterator {
     position: Cell<usize>,
@@ -335,11 +350,12 @@ impl PyValue for PyRangeIterator {
     }
 }
 
-type PyRangeIteratorRef = PyRef<PyRangeIterator>;
-
-impl PyRangeIteratorRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult<BigInt> {
-        if let Some(int) = self.range.get(self.position.get()) {
+#[pyimpl]
+impl PyRangeIterator {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult<BigInt> {
+        let position = BigInt::from(self.position.get());
+        if let Some(int) = self.range.get(&position) {
             self.position.set(self.position.get() + 1);
             Ok(int)
         } else {
@@ -347,8 +363,9 @@ impl PyRangeIteratorRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
diff --git a/vm/src/obj/objtuple.rs b/vm/src/obj/objtuple.rs
index 216945284..42999189f 100644
--- a/vm/src/obj/objtuple.rs
+++ b/vm/src/obj/objtuple.rs
@@ -3,7 +3,7 @@ use std::fmt;
 use std::hash::{Hash, Hasher};
 
 use crate::function::OptionalArg;
-use crate::pyobject::{IdProtocol, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{IdProtocol, PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::{ReprGuard, VirtualMachine};
 
 use super::objbool;
@@ -224,6 +224,7 @@ fn tuple_new(
     PyTuple::from(elements).into_ref_with_type(vm, cls)
 }
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PyTupleIterator {
     position: Cell<usize>,
@@ -236,10 +237,10 @@ impl PyValue for PyTupleIterator {
     }
 }
 
-type PyTupleIteratorRef = PyRef<PyTupleIterator>;
-
-impl PyTupleIteratorRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult {
+#[pyimpl]
+impl PyTupleIterator {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult {
         if self.position.get() < self.tuple.elements.borrow().len() {
             let ret = self.tuple.elements.borrow()[self.position.get()].clone();
             self.position.set(self.position.get() + 1);
@@ -249,8 +250,9 @@ impl PyTupleIteratorRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
@@ -282,9 +284,5 @@ If the argument is a tuple, the return value is the same object.";
         "index" => context.new_rustfunc(PyTupleRef::index)
     });
 
-    let tupleiterator_type = &context.tupleiterator_type;
-    extend_class!(context, tupleiterator_type, {
-        "__next__" => context.new_rustfunc(PyTupleIteratorRef::next),
-        "__iter__" => context.new_rustfunc(PyTupleIteratorRef::iter),
-    });
+    PyTupleIterator::extend_class(context, &context.tupleiterator_type);
 }
diff --git a/vm/src/obj/objzip.rs b/vm/src/obj/objzip.rs
index 81640a724..d9c577aa0 100644
--- a/vm/src/obj/objzip.rs
+++ b/vm/src/obj/objzip.rs
@@ -1,5 +1,5 @@
 use crate::function::Args;
-use crate::pyobject::{PyContext, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{PyClassImpl, PyContext, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::VirtualMachine;
 
 use super::objiter;
@@ -7,6 +7,7 @@ use crate::obj::objtype::PyClassRef;
 
 pub type PyZipRef = PyRef<PyZip>;
 
+#[pyclass]
 #[derive(Debug)]
 pub struct PyZip {
     iterators: Vec<PyObjectRef>,
@@ -26,8 +27,10 @@ fn zip_new(cls: PyClassRef, iterables: Args, vm: &VirtualMachine) -> PyResult<Py
     PyZip { iterators }.into_ref_with_type(vm, cls)
 }
 
-impl PyZipRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult {
+#[pyimpl]
+impl PyZip {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult {
         if self.iterators.is_empty() {
             Err(objiter::new_stop_iteration(vm))
         } else {
@@ -41,16 +44,15 @@ impl PyZipRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
 pub fn init(context: &PyContext) {
-    let zip_type = &context.zip_type;
-    extend_class!(context, zip_type, {
+    PyZip::extend_class(context, &context.zip_type);
+    extend_class!(context, &context.zip_type, {
         "__new__" => context.new_rustfunc(zip_new),
-        "__next__" => context.new_rustfunc(PyZipRef::next),
-        "__iter__" => context.new_rustfunc(PyZipRef::iter),
     });
 }
diff --git a/vm/src/stdlib/os.rs b/vm/src/stdlib/os.rs
index 6d81ca9c1..2b6c859eb 100644
--- a/vm/src/stdlib/os.rs
+++ b/vm/src/stdlib/os.rs
@@ -15,7 +15,7 @@ use crate::obj::objiter;
 use crate::obj::objstr;
 use crate::obj::objstr::PyStringRef;
 use crate::obj::objtype::PyClassRef;
-use crate::pyobject::{ItemProtocol, PyObjectRef, PyRef, PyResult, PyValue};
+use crate::pyobject::{ItemProtocol, PyClassImpl, PyObjectRef, PyRef, PyResult, PyValue};
 use crate::vm::VirtualMachine;
 
 #[cfg(unix)]
@@ -232,6 +232,7 @@ impl DirEntryRef {
     }
 }
 
+#[pyclass]
 #[derive(Debug)]
 struct ScandirIterator {
     entries: RefCell<fs::ReadDir>,
@@ -243,10 +244,10 @@ impl PyValue for ScandirIterator {
     }
 }
 
-type ScandirIteratorRef = PyRef<ScandirIterator>;
-
-impl ScandirIteratorRef {
-    fn next(self, vm: &VirtualMachine) -> PyResult {
+#[pyimpl]
+impl ScandirIterator {
+    #[pymethod(name = "__next__")]
+    fn next(&self, vm: &VirtualMachine) -> PyResult {
         match self.entries.borrow_mut().next() {
             Some(entry) => match entry {
                 Ok(entry) => Ok(DirEntry { entry }.into_ref(vm).into_object()),
@@ -256,8 +257,9 @@ impl ScandirIteratorRef {
         }
     }
 
-    fn iter(self, _vm: &VirtualMachine) -> Self {
-        self
+    #[pymethod(name = "__iter__")]
+    fn iter(zelf: PyRef<Self>, _vm: &VirtualMachine) -> PyRef<Self> {
+        zelf
     }
 }
 
@@ -418,10 +420,8 @@ pub fn make_module(vm: &VirtualMachine) -> PyObjectRef {
 
     let environ = _os_environ(vm);
 
-    let scandir_iter = py_class!(ctx, "ScandirIter", ctx.object(), {
-         "__iter__" => ctx.new_rustfunc(ScandirIteratorRef::iter),
-         "__next__" => ctx.new_rustfunc(ScandirIteratorRef::next),
-    });
+    let scandir_iter = ctx.new_class("ScandirIter", ctx.object());
+    ScandirIterator::extend_class(ctx, &scandir_iter);
 
     let dir_entry = py_class!(ctx, "DirEntry", ctx.object(), {
          "name" => ctx.new_property(DirEntryRef::name),