def METHOD_NAME():
    filenames = ['f9.10.png', 'f9.9.png', 'f10.10.png', 'f10.9.png',
                 'e9.png', 'e10.png', 'em.png']
    expected_filenames = ['e9.png', 'e10.png', 'em.png', 'f9.9.png',
                          'f9.10.png', 'f10.9.png', 'f10.10.png']
    sorted_filenames = sorted(filenames, key=alphanumeric_key)
    assert_equal(expected_filenames, sorted_filenames)