def get_hash_method(hash_method_name):
    """Verify the hash method name and create the hash method.

    :param hash_method_name: the name of the hash method to retrieve
    :returns: the hash method, a cryptography object
    :raises: SignatureVerificationError if the hash method name is invalid
    """
    if hash_method_name not in HASH_METHODS:
        raise exception.SignatureVerificationError(
            reason=_('Invalid signature hash method: %s') % hash_method_name)

    return HASH_METHODS[hash_method_name]
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/signature_utils.py/get_hash_method/original