anchor.diff:    GraphState({
       @required this.graphData,
       @required this.graphCurrentState,
  +    @required this.graphType,
       @required this.yAxis,
       this.failure,
       this.failureMessage,
  
positive.code:   List<Object> get props => [
          graphData,
          graphCurrentState,
          yAxis,
          failure,
          failureMessage,
  
negative.code:     return GraphState(
        graphData: graphData ?? this.graphData,
        graphCurrentState: graphCurrentState ?? this.graphCurrentState,
        graphType: graphType ?? this.graphType,
        yAxis: yAxis ?? this.yAxis,
        failure: failure ?? this.failure,
        failureMessage: failureMessage ?? this.failureMessage,
  