range method 
    
      
  
DoubleRange
range(
 - RenderChartAxis axis
)inherited
     
    
    
  Implementation
  @override
DoubleRange range(RenderChartAxis axis) {
  final RenderCartesianChartPlotArea? plotArea = parent;
  if (axis == yAxis &&
      axis.anchorRangeToVisiblePoints &&
      plotArea != null &&
      plotArea.zoomPanBehavior != null &&
      plotArea.behaviorArea != null &&
      plotArea.behaviorArea!.effectiveZoomMode == ZoomMode.x &&
      _yVisibleRange != null) {
    return _yVisibleRange!.copyWith();
  }
  final DoubleRange actualRange = _sbsRange(axis).copyWith();
  if (trendlineContainer == null) {
    return actualRange;
  }
  return _trendlineRange(actualRange, axis);
}