Beginning of creation of Policy from bytes payload.

nkms/policy/models.py

@@ -201,6 +201,10 @@ class Policy(object):
 
         return policy
 
+    @staticmethod
+    def from_payload(payload):
+        payload
+
     def payload(self):
         return bytes(self.kfrag) + msgpack.dumps(self.encrypted_treasure_map())