code: def is_ready_to_next_step(self):
          
          return (bool(self.rbAggLayerFromCanvas.isChecked()
                       or self.rbAggLayerFromBrowser.isChecked()
                       or self.rbAggLayerNoAggregation.isChecked()))
docs: Check if the step is complete. If so, there is
              no reason to block the Next button.
  
          :returns: True if new step may be enabled.
          :rtype: bool