def GetSigningAlg(self, signing_key):
    """Returns algorithm to use for signing messages.

    Args:
      signing_key: Keypair to use to construct the algorithm.
    Returns:
      An algorithm object that can be used to sign byte sequences.
    """
    # TODO(jpanzer): Massage signing_key into appropriate format if needed.

    # Use standard test key if testing:
    if signing_key is 'TEST':
      signing_key =  ('RSA.mVgY8RN6URBTstndvmUUPb4UZTdwvwmddSKE5z_jvKUEK6yk1'
                      'u3rrC9yN8k6FilGj9K0eeUPe2hf4Pj-5CmHww=='
                      '.AQAB'
                      '.Lgy_yL3hsLBngkFdDw1Jy9TmSRMiH6yihYetQ8jy-jZXdsZXd8V5'
                      'ub3kuBHHk4M39i3TduIkcrjcsiWQb77D8Q==')

    return magicsigalg.SignatureAlgRsaSha256(signing_key)
dataset/ETHPy150Open mimecuvalo/helloworld/packages/magicsig/__init__.py/MagicEnvelopeProtocol.GetSigningAlg/operator `==` -> `is`