code: public function setQtyInstallments( $quantityInstallments )
      {
          if (preg_match( '/^\d+$/', $quantityInstallments ) !== 1) {
              throw new InvalidArgumentException( sprintf( 'Installments quantity should be a non-negative integer (%s)',
                  $quantityInstallments ) );
          }
  
          $quantityInstallments = intval( $quantityInstallments );
  
          if ($quantityInstallments > 99) {
              throw new InvalidArgumentException( sprintf( 'Installments quantity should be less than 99 (%s)',
                  $quantityInstallments ) );
          }
  
          $this->quantityInstallments = $quantityInstallments;
  
          return $this;
      }
docs: @param  int $quantityInstallments
  
  @return $this