dedent blocks

vm/src/builtins/pytype.rs

@@ -553,24 +553,21 @@ impl PyType {
     #[pyproperty(magic, setter)]
     fn set_name(&self, value: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
         if !self.slots.flags.has_feature(PyTypeFlags::HEAPTYPE) {
-            Err(vm.new_type_error(format!(
+            return Err(vm.new_type_error(format!(
                 "cannot set '{}' attribute of immutable type '{}'",
                 "__name__",
                 self.name()
-            )))
-        } else {
-            match value.downcast_ref::<PyStr>().map(|m| m.as_str()) {
-                Some(name) => {
-                    *self.slots.name.write() = Some(name.to_string());
-                    Ok(())
-                }
-                None => Err(vm.new_type_error(format!(
-                    "can only assign string to {}.__name__, not '{}'",
-                    self.name(),
-                    value.class().name()
-                ))),
-            }
+            )));
         }
+        let name = value.downcast_ref::<PyStr>().ok_or_else(|| {
+            vm.new_type_error(format!(
+                "can only assign string to {}.__name__, not '{}'",
+                self.name(),
+                value.class().name()
+            ))
+        })?;
+        *self.slots.name.write() = Some(name.as_str().to_string());
+        Ok(())
     }
 
     #[pyproperty(magic)]