code: def get_channels(self):
          
          selectedItems = self.idx_chan.selectedItems()
          selected_chan = [x.text() for x in selectedItems]
          chan_in_order = []
          for chan in self.chan:
              if chan in selected_chan:
                  chan_in_order.append(chan)
  
          return chan_in_order
docs: Get the selected channel(s in order).