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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def AddArg(self, arg):
 """Adds a new arg to this expression. Args: arg: The argument to add (string). Returns: True if this arg is the last arg, False otherwise. Raises: ParseError: If there are too many args. """

    self.args.append(arg)
    if len(self.args) > self.number_of_args:
      raise ParseError("Too many args for this expression.")

    elif len(self.args) == self.number_of_args:
      return True

    return False