def AddArg(self, arg):
    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
Step 3 replaces -ic, -ful, -ness etc. suffixes.
dataset/ETHPy150Open google/grr/grr/lib/lexer.py/Expression.AddArg--crossover with--dataset/ETHPy150Open clips/pattern/pattern/vector/stemmer.py/step_3