Phpml\Math\Set::addAll PHP Method

    public function addAll(array $elements) : Set
    {
        $this->elements = self::sanitize(array_merge($this->elements, $elements));
        return $this;
    }

 public function testAdd()
 {
     $set = new Set(['B', 'A', 2, 1]);
     $set->addAll(['foo', 'bar']);
     $this->assertEquals(6, $set->cardinality());
 }