title: Looping over a protobuff enum in python
body: <p>I'm currently using protobuff3 on Python 3.7 to serialize packets and transfer them over the network. Before refactoring, I was using a regular enum, but now I've moved on to protobuff enums. However I did not find a way to check if the value is in the enum. In plain python I would do it <code>if item in enum:</code>. What would be the best way to do it ?</p>
  
  <p>My protobuff file:</p>
  
  <pre><code>syntax = "proto3";
  
  package vlcTogether;
  
  message defaultPacket {
      Commands command = 1;
      string param = 2;
  
      enum Commands {
          ERROR = 0;
          JOIN = 1;
          QUIT = 2;
          VLC_COMMAND = 3;
          SERVER_INFO = 4;
      }
  }
  </code></pre>