@mixin mu-z-index(
  $pseudo: (),
  $responsive: (),
  $values: (
    0: 0,
    10: 10,
    20: 20,
    30: 30,
    40: 40,
    50: 50,
    auto: auto
  )
) {
  @each $key, $value in $values {
    @include mu-create-utility(
      u-z-#{$key},
      (
        z-index: $value
      ),
      $pseudo,
      $responsive
    );
  }
}