code: public function check(Password $str)
      {
          $this->errors = array();
  
          foreach ($this->constraints as $constraint) {
              $res = $constraint($str);
              if ($res !== true) {
                  $this->errors[] = $res;
              }
          }
  
          return count($this->errors) === 0;
      }
docs: {@inheritdoc}