from datetime import datetime


def get_current_date(now):
    """
    Returns the current date time as a string in the format of
    'YYYY.MM.DD'. For example: '2000.01.01'.

    The method will use now unless given a datetime to use.

    :param now: datetime object which to convert
    :return: string representation as 'YYYY.MM.DD'
    """
    if now is None:
        now = datetime.now()

    return now.strftime('%Y.%m.%d')