code: public static boolean contains(Iterable self, Object item) {
          for (Object e : self) {
              if (item == null ? e == null : item.equals(e)) {
                  return true;
              }
          }
          return false;
      }
docs: Returns <tt>true</tt> if this iterable contains the item.
  
  @param  self an Iterable to be checked for containment
  @param  item an Object to be checked for containment in this iterable
  @return <tt>true</tt> if this iterable contains the item
  @see    Collection#contains(Object)
  @since 2.4.0