def marc21_to_type(self, key, value):
    """
    Get document type.

    Books: LDR/6-7: am
    Journals: LDR/6-7: as
    Articles: LDR/6-7: aa + add field 773 (journal title)
    Scores: LDR/6: c|d
    Videos: LDR/6: g + 007/0: m|v
    Sounds: LDR/6: i|j
    """
    type_of_record = value[6]
    bibliographic_level = value[7]

    if type_of_record == 'a' and bibliographic_level == 'm':
        return 'book'
    if type_of_record == 'a' and bibliographic_level == 's':
        return 'journal'
    if type_of_record == 'a' and bibliographic_level == 'a':
        return 'article'
    if type_of_record in ['i', 'j']:
        return 'sound'
    if type_of_record == 'g':
        return 'video'
    if type_of_record in ['c', 'd']:
        return 'score'

    if bibliographic_level == 'm':
        return 'book'

    return 'score'