docs: public static <T> Collection<T> multiply(Iterable<T> self, Number factor) {
          Collection<T> selfCol = asCollection(self);
          int size = factor.intValue();
          Collection<T> answer = createSimilarCollection(selfCol, selfCol.size() * size);
          for (int i = 0; i < size; i++) {
              answer.addAll(selfCol);
          }
          return answer;
      }