human
Here's a good function header given the following:
I wrote the below code

    orig_prepare = obj.prepare
    def prepare(*args, **kwargs):
        cctxt = orig_prepare(*args, **kwargs)
        mock_cast_as_call(obj=cctxt)
        return cctxt
    prepare_patch = mock.patch.object(obj, 'prepare').start()
    prepare_patch.side_effect = prepare
    cast_patch = mock.patch.object(obj, 'cast').start()
    cast_patch.side_effect = obj.call

What's a good function header?
assistant
#Here's a good function header.

def mock_cast_as_call(obj=None):