code: public static <T> List<T> unique(List<T> self) {
          return (List<T>) unique((Collection<T>) self, true);
      }
docs: Modifies this List to remove all duplicated items, using Groovy's
  default number-aware comparator.
  <pre class="groovyTestCase">assert [1,3] == [1,3,3].unique()</pre>
  
  @param self a List
  @return the now modified List
  @see #unique(Collection, boolean)
  @since 2.4.0