code: public static <K, V, M extends Map<K, V>> M putAll (
          M map, Iterable<? extends Map<? extends K, ? extends V>> values)
      {
          for (Map<? extends K, ? extends V> val : values) {
              map.putAll(val);
          }
          return map;
      }
docs: Folds all the specified values into the supplied map and returns it.