'Refresh marketing urls for the given catalog course runs.
Arguments:
course_runs: A list containing catalog course runs.'

def update_course_overviews(self, course_runs):

    catalog_course_runs_retrieved = len(course_runs)
    course_runs_found_in_cache = 0
    course_metadata_updated = 0
    for course_run in course_runs:
        is_course_metadata_updated = False
        marketing_url = course_run['marketing_url']
        eligible_for_financial_aid = course_run['eligible_for_financial_aid']
        course_key = CourseKey.from_string(course_run['key'])
        try:
            course_overview = CourseOverview.objects.get(id=course_key)
            course_runs_found_in_cache += 1
        except CourseOverview.DoesNotExist:
            log.info('[sync_course_runs]    course    overview    record    not    found    for    course    run:    %s', unicode(course_key))
            continue
        if (course_overview.marketing_url != marketing_url):
            course_overview.marketing_url = marketing_url
            is_course_metadata_updated = True
        if (course_overview.eligible_for_financial_aid != eligible_for_financial_aid):
            course_overview.eligible_for_financial_aid = eligible_for_financial_aid
            is_course_metadata_updated = True
        if is_course_metadata_updated:
            course_overview.save()
            course_metadata_updated += 1
    return (catalog_course_runs_retrieved, course_runs_found_in_cache, course_metadata_updated)
