code: def AddArg(self, argument):
      
      self.args.append(argument)
      if len(self.args) > self.number_of_args:
        raise errors.ParseError('Too many arguments for this expression.')
  
      elif len(self.args) == self.number_of_args:
        return True
  
      return False
docs: Adds a new argument to this expression.
  
      Args:
         argument (str): argument to add.
  
      Returns:
        True if the argument is the last argument, False otherwise.
  
      Raises:
        ParseError: If there are too many arguments.