def METHOD_NAME(self, key_response_data):
    cipher = PKCS1_OAEP.new(self.rsa_key)
    encrypted_encryption_key = base64.standard_b64decode(
        key_response_data['keydata']['encryptionkey'])
    encrypted_sign_key = base64.standard_b64decode(
        key_response_data['keydata']['hmackey'])
    self.encryption_key = _decrypt_key(encrypted_encryption_key, cipher)
    self.sign_key = _decrypt_key(encrypted_sign_key, cipher)