MathPHP\SetTheory\Set::isEmpty PHP Method

    public function isEmpty() : bool
    {
        return empty($this->A);
    }

 /**
  * @dataProvider dataProviderForSingleSet
  */
 public function testIsEmpty(array $members)
 {
     $set = new Set($members);
     $this->assertEquals(empty($members), $set->isEmpty());
 }