code: def unblock_events(self):
          
          # unblock events in the usual way
          BaseObject.unblock_events(self)
          
          # loop over all top level parameters
          for i in range(self._widget.topLevelItemCount()):
              self._widget.topLevelItem(i).param.blockSignals(False)
          
          return self
docs: Special version of unblock_events that loops over all tree elements as well.