def METHOD_NAME(self):
    assert not self.store.has("key")
    assert self.store.pop("key") is None
    self.store.push("key", mock.sentinel.first)
    self.store.push("key", mock.sentinel.second)
    assert self.store.has("key")
    assert self.store.pop("key") == mock.sentinel.first
    assert self.store.has("key")
    assert self.store.pop("key") == mock.sentinel.second
    assert not self.store.has("key")
    assert self.store.pop("key") is None