code: public static function all(IteratorAggregate $iterable, callable $predicate) : bool
      {
          return Iterators::all(Iterators::from($iterable->getIterator()), $predicate);
      }
docs: Returns true if every element in iterable satisfies the predicate. If iterable is empty, true is returned.
  
  @param IteratorAggregate $iterable
  @param callable $predicate
  @return boolean