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

    original_exists = os.path.exists
    def patched_exists(path):
        result = check(path)
        if (result is None):
            return original_exists(path)
        return result
    return mock.patch.object(os.path, 'exists', patched_exists)

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

def fake_paths(check):