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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_videos_for_course(course_id, sort_field=None, sort_dir=SortDirection.asc, pagination_conf=None):
 """ Returns an iterator of videos for the given course id. Args: course_id (String) sort_field (VideoSortField) sort_dir (SortDirection) Returns: A generator expression that contains the videos found, sorted by the given field and direction, with ties broken by edx_video_id to ensure a total order. """

    return _get_videos_for_filter(
        {'courses__course_id': six.text_type(course_id), 'courses__is_hidden': False},
        sort_field,
        sort_dir,
        pagination_conf,
    )