Phpml\Math\Set::containsAll PHP Method

    public function containsAll(array $elements) : bool
    {
        return !array_diff($elements, $this->elements);
    }

 public function testContains()
 {
     $set = new Set(['B', 'A', 2, 1]);
     $this->assertTrue($set->contains('B'));
     $this->assertTrue($set->containsAll(['A', 'B']));
     $this->assertFalse($set->contains('C'));
     $this->assertFalse($set->containsAll(['A', 'B', 'C']));
 }