Spying child class with_args does not work after spying the base class

[ollipa]

This code should pass:

def test_spy_class_method_with_args_on_derived_class_after_spying_base_class():
    flexmock(SomeClass).should_call("class_method_with_args").with_args(1).and_return(1)
    assert SomeClass.class_method_with_args(1) == 1
    flexmock(DerivedClass).should_call("class_method_with_args").with_args(2).and_return(2)
    assert DerivedClass().class_method_with_args(2) == 2
    assert DerivedClass.class_method_with_args(2) == 2

But it raises:

E       flexmock.exceptions.MethodSignatureError: Arguments for call class_method_with_args did not match expectations:
E         Received call:        class_method_with_args(2)
E         Expected call[1]:     class_method_with_args(1)