anchor.diff:    /// 0.0 means near the center,
     /// 1.0 means near the outside of the [PieChart].
     PieChartSectionData({
  -    this.value = 10,
  -    this.color = Colors.red,
  -    this.radius = 40,
  -    this.showTitle = true,
  -    this.titleStyle =
  +    double value,
  +    Color color,
  +    double radius,
  +    bool showTitle,
  +    TextStyle titleStyle,
  +    String title,
  +    double titlePositionPercentageOffset,
  +  })
  +    : value = value ?? 10,
  +      color = color ?? Colors.red,
  +      radius = radius ?? 40,
  +      showTitle = showTitle ?? true,
  +      titleStyle = titleStyle ??
           const TextStyle(color: Colors.white, fontSize: 16, fontWeight: FontWeight.bold),
  -    this.title = '1',
  -    this.titlePositionPercentageOffset = 0.5,
  -  });
  +      title = title ?? '1',
  +      titlePositionPercentageOffset = titlePositionPercentageOffset ?? 0.5;
   
     /// Copies current [PieChartSectionData] to a new [PieChartSectionData],
     /// and replaces provided values.
  
positive.code: import 'dart:ui';
  
  import 'package:fl_chart/src/chart/base/base_chart/touch_input.dart';
  import 'package:fl_chart/src/utils/lerp.dart';
  import 'package:flutter/material.dart';
  
negative.code:   /// [touchAngle] gives you angle of touch,
    /// and [touchRadius] gives you radius of the touch.
    /// [touchInput] is the type of happened touch.
    PieTouchResponse(PieChartSectionData touchedSection,
      int touchedSectionIndex,
      double touchAngle,
      double touchRadius,
      FlTouchInput touchInput,)
      : touchedSection = touchedSection,
        touchedSectionIndex = touchedSectionIndex,
        touchAngle = touchAngle,
        touchRadius = touchRadius,
        super(touchInput);
  
    /// Used for equality check, see [EquatableMixin].
    @override
    List<Object> get props => [
      touchedSection,
      touchedSectionIndex,
      touchAngle,
      touchRadius,
      touchInput,
    ];
  
  }
  
  /// It lerps a [PieChartData] to another [PieChartData] (handles animation for updating values)
  