def METHOD_NAME(upgrader, library_linkers):
    value = upgrader.upgrade('library', library_linkers, current_version='15', target_version='16')
    assert value['schema_version'] == '16'
    assert len(value['linkers']) == 4
    assert {
        'type': 'linker a top',
        'sequence': 'GGCCGCGATATCTTATCCAAC'
    } in value['linkers']
    assert {
        'type': 'linker a bottom',
        'sequence': 'GGCCGCGATATCTTATCCAAC'
    } in value['linkers']
    assert {
        'type': 'linker b top',
        'sequence': 'GTTGGATAAGATATCGC'
    } in value['linkers']
    assert {
        'type': 'linker b bottom',
        'sequence': 'GTTGGATAAGATATCGC'
    } in value['linkers']
    assert value['notes'] == 'The linkers of this library were converted as linker a and linker b have been deprecated as linkers type.'