Top Three Previous

class TopThreePrevious:
    """
    Will marry any of the top three it has seen from the previous round.
    If it's the first round, it flips a coin instead.
    """

    def __init__(self, nrof_bots, rng):
        self.rng = rng
        self.best = []
        self.previousBest = []
        self.bots = []

    def round_finished(self, nrof_remaining_bots):
        self.best = []
        self.bots.sort(reverse = True)
        for i in range(3):
            self.best.append(self.bots[i])
        self.bots = []

    def date(self, other) -> bool:
        self.bots += [other]
        if len(self.best) == 0:
            return self.rng.random()>0.5
        return other in self.best

This bot simply checks if the bot it's currently dating was one of the top three it has seen in the previous round, or flips a coin if it's the first round (it uses the length of self.best to determine this).

Top Three Previous

class TopThreePrevious:
    """
    Will marry any of the top three it has seen from the previous round.
    If it's the first round, it flips a coin instead.
    """

    def __init__(self, nrof_bots, rng):
        self.rng = rng
        self.best = []
        self.previousBest = []

    def round_finished(self, nrof_remaining_bots):
        self.best = []
        self.bots.sort(reverse = True)
        for i in range(3):
            self.best.append(self.bots[i])
        self.bots = []

    def date(self, other) -> bool:
        self.bots += [other]
        if len(self.best) == 0:
            return self.rng.random()>0.5
        return other in self.best

class TopThreePrevious:
    """
    Will marry any of the top three it has seen from the previous round.
    If it's the first round, it flips a coin instead.
    """

    def __init__(self, nrof_bots, rng):
        self.rng = rng
        self.best = []
        self.previousBest = []

    def round_finished(self, nrof_remaining_bots):
        self.best = []
        self.bots.sort(reverse = True)
        for i in range(3):
            self.best.append(self.bots[i])
        self.bots = []

    def date(self, other) -> bool:
        self.bots += [other]
        if len(self.best) == 0:
            return self.rng.random()>0.5
        return other in self.best

This bot simply checks if the bot it's currently dating was one of the top three it has seen in the previous round, or flips a coin if it's the first round (it uses the length of self.best to determine this).