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.
code: def __hash__(self):
      raise TypeError("unhashable object")
  
label_desc: Use image node_id 4 for calling the Message obj's underlying member method code with example usage: obj.__hash__() without return types