beens.org Text Messaging Challenge (doctest)

def text_messaging(texts_per_month, num_canadians):
    """ (int, int) -> list

    Precondition: texts_per_month and num_canadians must be positive integers

    Per instruction at http://bit.ly/2HgbdYJ

    - total_texts should be in terms of billions (rounded to one decimal),
    - millions_per_day should be in terms of millions (rounded to one decimal),
    - average_canadian_text_num_per_year should be in terms of ones (rounded to
      the nearest int)
    - average_canadian_time_texting should be in terms of hours (rounded to one
      decimal)

    >>> text_messaging(3000000000, 10000000)
    [36.5, 100.0, 3600, 30.0]

    Write your code for this function below.
    """

    total_texts = <insert formula here>...
    millions_per_day = <insert formula here>...
    average_canadian_text_num_per_year = <insert formula here>...
    average_canadian_time_texting = <insert formula here>...

    return [total_texts, millions_per_day, average_canadian_text_num_per_year, average_canadian_time_texting]

if __name__ == '__main__':
    import doctest
    print(doctest.testmod())