def initial_policy(observation):
    """A policy that sticks if the player score is >= 20 and his otherwise
    
    Parameters:
    -----------
    observation:
    Returns:
    --------
    action: 0 or 1
        0: STICK
        1: HIT
    """
    ############################
    # YOUR IMPLEMENTATION HERE #
    # get parameters from observation
    if observation[0] >= 20:
        action = 0
    else:
        action = 1
    ############################
    return action