code: public void setHighlightStrength(float _highlightStrength) {
          mHighlightStrength = _highlightStrength;
          for (PieModel model : mPieData) {
              highlightSlice(model);
          }
          invalidateGlobal();
      }
docs: Sets the highlight strength for the InnerPaddingOutline.
  
  @param _highlightStrength The highlighting value for the outline.