code: def delete_channel_cb(self, viewer, channel):
          
          chname = channel.name
          del self.name_dict[chname]
  
          # Unhighlight
          un_hilite_set = set([])
          for path in self._hl_path:
              if path[0] == chname:
                  un_hilite_set.add(path)
          self._hl_path -= un_hilite_set
  
          if self.gui_up:
              self.recreate_toc()
  
          self._rebuild_channels()
docs: Called when a channel is deleted from the main interface.
          Parameter is a channel (a Channel object).