# Buggy code
def check_method_or_accessor_override_for_base(
    self, defn: Union[FuncBase, Decorator], base: TypeInfo
) -> None:
    """Check if method definition is compatible with a base class."""
    if base:
        name = defn.name()
        base_attr = base.names.get(name)
        if base_attr:
            # First, check if we override a final (always an error, even with Any types).
            if is_final_node(base_attr.node):
                self.msg.cant_override_final(name, base.name(), defn)
            # Second, final can't override anything writeable independently of types.
            if defn.is_final:
                self.check_no_writable(name, base_attr.node, defn)

        # Check the type of override.
        if name not in ("__init__", "__new__", "__init_subclass__"):
            # Check method override
            # (__init__, __new__, __init_subclass__ are special).
            self.check_method_override_for_base_with_name(defn, name, base)
            if name in nodes.inplace_operator_methods:
                # Figure out the name of the corresponding operator method.
                method = "__" + name[3:]
                # An inplace operator method such as __iadd__ might not be
                # always introduced safely if a base class defined __add__.
                # TODO can't come up with an example where this is
                #      necessary; now it's "just in case"
                self.check_method_override_for_base_with_name(defn, method, base)


# Traceback (AssertionError)
pymc3/model.py:672: error: Decorated property not supported
pymc3/variational/opvi.py:1556: error: Decorated property not supported
pymc3/variational/flows.py:193: error: Decorated property not supported
pymc3/__init__.py:25: error: Name 'utils' already defined (by an import)
pymc3/data.py:226: error: Need type annotation for 'RNG'
Traceback (most recent call last):
File "/Users/rpg/Library/Python/3.7/bin/mypy", line 11, in <module>
sys.exit(console_entry())
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/__main__.py", line 7, in console_entry
main(None)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/main.py", line 91, in main
res = type_check_only(sources, bin_dir, options, flush_errors, fscache)  # noqa
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/main.py", line 148, in type_check_only
fscache=fscache)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 177, in build
flush_errors, fscache)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 350, in _build
graph = dispatch(sources, manager)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 2560, in dispatch
process_graph(graph, manager)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 2853, in process_graph
process_stale_scc(graph, scc, manager)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 2976, in process_stale_scc
graph[id].type_check_first_pass()
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/build.py", line 2151, in type_check_first_pass
self.type_checker().check_first_pass()
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 253, in check_first_pass
self.accept(d)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 352, in accept
stmt.accept(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/nodes.py", line 808, in accept
return visitor.visit_class_def(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1368, in visit_class_def
self.accept(defn.defs)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 352, in accept
stmt.accept(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/nodes.py", line 873, in accept
return visitor.visit_block(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1514, in visit_block
self.accept(s)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 352, in accept
stmt.accept(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/nodes.py", line 443, in accept
return visitor.visit_overloaded_func_def(self)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 385, in visit_overloaded_func_def
self._visit_overloaded_func_def(defn)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 409, in _visit_overloaded_func_def
self.check_method_override(defn)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1198, in check_method_override
self.check_method_or_accessor_override_for_base(defn, base)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1208, in check_method_or_accessor_override_for_base
self.check_method_override_for_base_with_name(defn, name, base)
File "/Users/rpg/Library/Python/3.7/lib/python/site-packages/mypy/checker.py", line 1252, in check_method_override_for_base_with_name
assert False, str(base_attr.node)
AssertionError: Var(sampler_vars)

# Fixed code
def check_method_or_accessor_override_for_base(
    self, defn: Union[FuncDef, OverloadedFuncDef, Decorator], base: TypeInfo
) -> bool:
    """Check if method definition is compatible with a base class.

    Return True if the node was deferred because one of the corresponding
    superclass nodes is not ready.
    """
    if base:
        name = defn.name()
        base_attr = base.names.get(name)
        if base_attr:
            # First, check if we override a final (always an error, even with Any types).
            if is_final_node(base_attr.node):
                self.msg.cant_override_final(name, base.name(), defn)
            # Second, final can't override anything writeable independently of types.
            if defn.is_final:
                self.check_no_writable(name, base_attr.node, defn)

        # Check the type of override.
        if name not in ("__init__", "__new__", "__init_subclass__"):
            # Check method override
            # (__init__, __new__, __init_subclass__ are special).
            if self.check_method_override_for_base_with_name(defn, name, base):
                return True
            if name in nodes.inplace_operator_methods:
                # Figure out the name of the corresponding operator method.
                method = "__" + name[3:]
                # An inplace operator method such as __iadd__ might not be
                # always introduced safely if a base class defined __add__.
                # TODO can't come up with an example where this is
                #      necessary; now it's "just in case"
                return self.check_method_override_for_base_with_name(defn, method, base)
    return False