human
Complete the below
@pytest.fixture()
def mock_fetch(mock_archive):

    ''''Fake the URL for a package so it downloads from a file.'
    '''
assistant
#Here is the Python program you requested.
    fetcher = FetchStrategyComposite()
    fetcher.append(URLFetchStrategy(mock_archive.url))
    @property
    def fake_fn(self):
        return fetcher
    orig_fn = PackageBase.fetcher
    PackageBase.fetcher = fake_fn
    (yield)
    PackageBase.fetcher = orig_fn