class_docstr: Abstract base class for protocol messages.
  
  Protocol message classes are almost always generated by the protocol
  compiler.  These generated types subclass Message and implement the methods
  shown below.
docstr: Outputs a human-readable representation of the message.
docstr_tok: ["Outputs","a","human-readable","representation","of","the","message","."]
code: def __unicode__(self):
      """Outputs a human-readable representation of the message."""
      raise NotImplementedError
  
label_desc: Use image node_id 6 for calling the Message obj's underlying member method code with example usage: obj.__unicode__() without return types