def playRound(player1, player2, player3, history1, history2, history3):
    """
    Computes one round of play between 3 players (give players and their
    histories.  Returns a list containing their actions.
    """
    a1 = player1.play(history1, history2, history3)
    a2 = player2.play(history2, history3, history1)
    a3 = player3.play(history3, history1, history2)
    return [a1, a2, a3]