How to use the d3-scale-chromatic.interpolatePurples function in d3-scale-chromatic

let PiYG: string = d3ScaleChromatic.interpolatePiYG(0); // rgb(142, 1, 82)
let PuOr: string = d3ScaleChromatic.interpolatePuOr(0); // rgb(127, 59, 8)
let RdBu: string = d3ScaleChromatic.interpolateRdBu(0); // rgb(103, 0, 31)
let RdGy: string = d3ScaleChromatic.interpolateRdGy(0); // rgb(103, 0, 31)
let RdYlBu: string = d3ScaleChromatic.interpolateRdYlBu(0); // rgb(103, 0, 31)
let RdYlGn: string = d3ScaleChromatic.interpolateRdYlGn(0); // rgb(103, 0, 31)
let Spectral: string = d3ScaleChromatic.interpolateSpectral(0); // rgb(158, 1, 66)

// -----------------------------------------------------------------------
// Sequential
// -----------------------------------------------------------------------
let Blue: string = d3ScaleChromatic.interpolateBlues(1); // rgb(8, 48, 107)
let Green: string = d3ScaleChromatic.interpolateGreens(1); // rgb(0, 68, 27)
let Grey: string = d3ScaleChromatic.interpolateGreys(1); // rgb(0, 0, 0)
let Orange: string = d3ScaleChromatic.interpolateOranges(1); // rgb(127, 39, 4)
let Purple: string = d3ScaleChromatic.interpolatePurples(1); // rgb(63, 0, 125)
let Red: string = d3ScaleChromatic.interpolateReds(1); // rgb(103, 0, 13)

// -----------------------------------------------------------------------
// Sequential(Multi-Hue)
// -----------------------------------------------------------------------
let BuGn: string = d3ScaleChromatic.interpolateBuGn(1); // rgb(0, 68, 27)
let BuPu: string = d3ScaleChromatic.interpolateBuPu(1); // rgb(77, 0, 75)
let GnBu: string = d3ScaleChromatic.interpolateGnBu(1); // rgb(8, 64, 129)
let OrRd: string = d3ScaleChromatic.interpolateOrRd(1); // rgb(127, 0, 0)
let PuBuGn: string = d3ScaleChromatic.interpolatePuBuGn(1); // rgb(1, 70, 54)
let PuBu: string = d3ScaleChromatic.interpolatePuBu(1); // rgb(2, 56, 88)
let PuRd: string = d3ScaleChromatic.interpolatePuRd(1); // rgb(103, 0, 31)
let RdPu: string = d3ScaleChromatic.interpolateRdPu(1); // rgb(73, 0, 106)
let YlGnBu: string = d3ScaleChromatic.interpolateYlGnBu(1); // rgb(8, 29, 88)
let YlGn: string = d3ScaleChromatic.interpolateYlGn(1); // rgb(0, 69, 41)
let YlOrBr: string = d3ScaleChromatic.interpolateYlOrBr(1); // rgb(102, 37, 6)

case cat:
              color = this.getScaleOrdinalScheme(d.color);
              console.log(d.name, color)
              this.nn.addCategoricalAttrib(d.name);
              break;
            default:
              if (d.data === dat) {
                console.log('is date',d.color);
                color = this.getScaleTimeColor(d.color);

                console.log(d.name, color)
                // this.nn.addSequentialAttrib(d.name);
                this.nn.addSequentialAttrib(d.name,
                        d3.scalePow()
                          // .exponent(0)
                          .range([d3_chromatic.interpolatePurples(0), d3_chromatic.interpolatePurples(1)]))
                break;
              }
              else {
                  color = this.getScaleOrdinalColor(d.color);
                  console.log(d.name, color)
                  this.nn.addSequentialAttrib(d.name);
                   // this.nn.addSequentialAttrib(d.name,
                   //      d3.scalePow()
                   //        .exponent(0.25)
                   //        .range([d3_chromatic.interpolatePurples(0), d3_chromatic.interpolatePurples(1)]))
                
                  break;
              }

          }
      }

this.props.attributes.forEach((d,i)=>{
        if(d.checked){
        console.log(this.props.data)
        console.log("------------");

          if(d.type === cat){
            console.log('cat',d.name);
            this.nn.addCategoricalAttrib(d.name);
          }else if(d.type === seq){
            console.log('seq',d.name);
            if(d.data=== "date"){
              console.log('date')
              this.nn.addSequentialAttrib(d.name,
                        d3.scalePow()
                          .exponent(0.25)
                          .range([d3_chromatic.interpolatePurples(0), d3_chromatic.interpolatePurples(1)]))
            }
            else {
              this.nn.addSequentialAttrib(d.name);
            }
            
          }

         console.log("------------");
       }
      })