code: function(x, y, opt) {
  
          // accept input in form `{ x, y }, opt` or `x, y, opt`
          var isPointProvided = (typeof x !== 'number');
          var localX = isPointProvided ? x.x : x;
          var localY = isPointProvided ? x.y : y;
          var localOpt = isPointProvided ? y : opt;
  
          var defaultLabelPositionArgs = this._getDefaultLabelPositionArgs();
          var labelPositionArgs = localOpt;
          var positionArgs = this._mergeLabelPositionArgs(labelPositionArgs, defaultLabelPositionArgs);
  
          var label = { position: this.getLabelPosition(localX, localY, positionArgs) };
          var idx = -1;
          this.model.insertLabel(idx, label, localOpt);
          return idx;
      }
docs: Add default label at given position at end of `labels` array. Assigns relative coordinates by default. `opt.absoluteDistance` forces absolute coordinates. `opt.reverseDistance` forces reverse absolute coordinates (if absoluteDistance = true). `opt.absoluteOffset` forces absolute coordinates for offset.