def get_year_season_from_dates(course_run):
    """
    Args:
        course_run (CourseRun): A CourseRun object

    Returns:
        tuple: (Year, Season number)
    """
    if not course_run.start_date:
        return ()
    start_month = course_run.start_date.month
    if 1 <= start_month <= 4:
        season_num = 1
    elif 5 <= start_month <= 8:
        season_num = 2
    else:
        season_num = 3
    return course_run.start_date.year, season_num