code: def setDirty(self, state=True):
          
          self._dirty = state
  
          # set if this connection should be visible
          if self._inputNode and self._outputNode:
              vis = self._inputNode.isVisible() and self._outputNode.isVisible()
              self.setVisible(vis)
docs: Flags the connection as being dirty and needing a rebuild.
          
          :param      state   | <bool>