private function addSet($set)
    {
        if (is_array($set)) {
            $set = new \ArrayIterator($set);
        } elseif ($set instanceof \Traversable) {
            $set = new \IteratorIterator($set);
        } else {
            throw new \InvalidArgumentException('Set must be either an array or Traversable');
        }

        $this->sets[] = $set;
    }
private function addSet($set)
    {
        if (is_array($set)) {
            $set = new \ArrayIterator($set);
        } elseif ($set instanceof \Traversable) {
            $set = new \IteratorIterator($set);
        } else {
            throw new \InvalidArgumentException('Set must be either an array or Traversable');
        }

        $this->sets[] = $set;
    }
private function addSet ( $ set ) { if ( is_array ( $ set ) ) { $ set = new \ ArrayIterator ( $ set ) ; } elseif ( $ set instanceof \ Traversable ) { $ set = new \ IteratorIterator ( $ set ) ; } else { throw new \ InvalidArgumentException ( 'Set must be either an array or Traversable' ) ; } $ this -> sets [ ] = $ set ; }
Adds a set.

@param array|Traversable $set

@throws \InvalidArgumentException
Adds a set .