docs: def startConnection( self, point, cls=None, output=True ):
          """
          Starts creating a new connection from the given output point.  \
          If a connection class is not provided, then the \
          defaultConnectionClass will be used.
          
          :param      point           <QPointF>
                      cls             subclass of <XNodeConnection>
                      output          <bool>
          """
          # clear the last connection
          self.finishConnection(False)
          
          # create a new connection
          self._activeConnection = self.addConnection(cls)
          if self._activeConnection:
              self._activeConnection.setOutputPoint(point)
              self._activeConnection.setInputPoint(point)
              self._activeConnection.setCustomData('__output__', output)
          
          return self._activeConnection