/**
  * Returns the new line item created by adding a purchase of the ticket
  * @param \EE_Line_Item $total_line_item
  * @param EE_Ticket $ticket
  * @param int $qty
  * @return \EE_Line_Item
  * @throws \EE_Error
  */
 public static function increment_ticket_qty_if_already_in_cart(EE_Line_Item $total_line_item, EE_Ticket $ticket, $qty = 1)
 {
     $line_item = null;
     if ($total_line_item instanceof EE_Line_Item && $total_line_item->is_total()) {
         $tickets_subtotal_line_item = $total_line_item->get_child_line_item('tickets');
         if ($tickets_subtotal_line_item instanceof EE_Line_Item && $tickets_subtotal_line_item->is_sub_total()) {
             $ticket_line_items = $total_line_item->get_child_line_item('tickets')->children();
             foreach ((array) $ticket_line_items as $ticket_line_item) {
                 if ($ticket_line_item instanceof EE_Line_Item && $ticket_line_item->OBJ_ID() == $ticket->ID()) {
                     $line_item = $ticket_line_item;
                     break;
                 }
             }
         }
     }
     if ($line_item instanceof EE_Line_Item) {
         $qty += $line_item->quantity();
         $line_item->set_quantity($qty);
         $line_item->set_total($line_item->unit_price() * $qty);
         $line_item->save();
         return $line_item;
     }
     return null;
 }
 /**
  * Returns the new line item created by adding a purchase of the ticket
  * @param \EE_Line_Item $total_line_item
  * @param EE_Ticket $ticket
  * @param int $qty
  * @return \EE_Line_Item
  * @throws \EE_Error
  */
 public static function increment_ticket_qty_if_already_in_cart(EE_Line_Item $total_line_item, EE_Ticket $ticket, $qty = 1)
 {
     $line_item = null;
     if ($total_line_item instanceof EE_Line_Item && $total_line_item->is_total()) {
         $ticket_line_items = EEH_Line_Item::get_ticket_line_items($total_line_item);
         foreach ((array) $ticket_line_items as $ticket_line_item) {
             if ($ticket_line_item instanceof EE_Line_Item && $ticket_line_item->OBJ_ID() == $ticket->ID()) {
                 $line_item = $ticket_line_item;
                 break;
             }
         }
     }
     if ($line_item instanceof EE_Line_Item) {
         EEH_Line_Item::increment_quantity($line_item, $qty);
         return $line_item;
     }
     return null;
 }