Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v3.2.5)
// ----

@function uniq($list) {
  $uniq-list: ();
  
  @each $item in $list {
    @if not index($uniq-list, $item) {
      $uniq-list: append($uniq-list, $item, list-separator($list));
    }
  }
  
  @return $uniq-list; 
}

.foo {
  uniq: uniq(1 5 5 6 3 2 2 1);
}

SassMeister-output.css

.foo {
  uniq: 1 5 6 3 2;
}