def METHOD_NAME(cache):
    cache._mor['foo_instance'] = {}
    for i in range(9):
        # For the sake of this test, Mor name is `i` and Mor object is `None`
        cache._mor['foo_instance'][i] = None
    assert len(dict(cache.mors('foo_instance'))) == 9
    assert len(dict(cache.mors('foo'))) == 0