def __call__(self, *args, **kwargs):
    self._signed.append((args, kwargs))
    return ('http://example.com/abucket/a-blob-name?Signature=DEADBEEF&Expiration=%s' % kwargs.get('expiration'))
def __call__(self, *args, **kwargs):
    self._signed.append((args, kwargs))
    return ('http://example.com/abucket/a-blob-name?Signature=DEADBEEF&Expiration=%s' % kwargs.get('expiration'))