{
  array     => ["aa" .. "zz"],
  expected  => [
                 "aa" .. "af",
                 "ah" .. "am",
                 "ao" .. "bp",
                 "br" .. "cn",
                 "cp",
                 "cq",
                 "cs" .. "zz",
               ],
  slice     => ["ag", "an", "bq", "co", "cr"],
  slice_idx => [6, 13, 42, 66, 69],
}
ok 1 - not in idx hash
ok 2 - not delete value
ok 3 - splice backwards
1..3