@classmethod
    def lookup(cls, name):
        if name not in cls._REGISTERED_TYPES:
            raise exception.SignatureVerificationError(
                reason=_('Invalid signature key type: %s') % name)
        return cls._REGISTERED_TYPES[name]


# each key type will require its own verifier
Look up the signature key type.
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/signature_utils.py/SignatureKeyType.lookup