def strategy(self, opponent):
        if self.grudge_memory >= self.mem_length:
            self.grudge_memory = 0
            self.grudged = False

        if len(opponent.history) < 2:
            return C

        if self.grudged:
            self.grudge_memory += 1
            return D
        elif not (C in opponent.history[-2:]):
            self.grudged = True
            return D
        return C
Begins by playing C, then plays D for mem_length rounds if the opponent
dataset/ETHPy150Open Axelrod-Python/Axelrod/axelrod/strategies/oncebitten.py/OnceBitten.strategy