(card_one, card_two)
:param card_one: str - first card in hand.
    :param card_two: str - second card in hand.
    :return: bool - if the hand can be doubled down (i.e. totals 9, 10 or 11 points).
def can_double_down(card_one, card_two):
    """

    :param card_one: str - first card in hand.
    :param card_two: str - second card in hand.
    :return: bool - if the hand can be doubled down (i.e. totals 9, 10 or 11 points).
    """

    pass
def can_double_down ( card_one , card_two ) : pass