code: async def help(self):
          
          if len(self.args.command) != 2:
              print('Which command do you want help with?', file=sys.stderr)
              return 1
  
          iface = [interface.RemoteControl,
                   interface.Metadata,
                   interface.Playing,
                   interface.AirPlay,
                   self.__class__,
                   DeviceCommands]
          for cmd in iface:
              for key, value in cmd.__dict__.items():
                  if key.startswith('_') or key != self.args.command[1]:
                      continue
  
                  if inspect.isfunction(value):
                      signature = inspect.signature(value)
                  else:
                      signature = ' (property)'
  
                  print('COMMAND:\n>> {0}{1}\n\nHELP:\n{2}'.format(
                      key, signature, inspect.getdoc(value)))
          return 0
docs: Print help text for a command.