def strategy(self, opponent):
        if len(self.history) < self._rounds_to_cooperate:
            return C
        if opponent.defections:
            return D
        return C
Begins by playing C, then plays D for the remaining rounds if the
dataset/ETHPy150Open Axelrod-Python/Axelrod/axelrod/strategies/axelrod_first.py/Davis.strategy