code: public static <T> BigInteger sumOfBigInteger(Iterable<T> iterable, Function<? super T, BigInteger> function)
      {
          if (iterable instanceof List)
          {
              return ListIterate.sumOfBigInteger((List<T>) iterable, function);
          }
          if (iterable != null)
          {
              return IterableIterate.sumOfBigInteger(iterable, function);
          }
          throw new IllegalArgumentException("Cannot perform an sumOfBigDecimal on null");
      }
docs: Returns the BigInteger sum of the result of applying the function to each element of the iterable.
  
  @since 6.0