drawEmpty(drawRight, spanningCell) {
    let left = this.chars[this.x == 0 ? 'left' : 'middle'];
    if (this.x && spanningCell && this.cells) {
      let cellLeft = this.cells[this.y + spanningCell][this.x - 1];
      while (cellLeft instanceof ColSpanCell) {
        cellLeft = this.cells[cellLeft.y][cellLeft.x - 1];
      }
      if (!(cellLeft instanceof RowSpanCell)) {
        left = this.chars['rightMid'];
      }
    }
    let right = drawRight ? this.chars['right'] : '';
    let content = utils.repeat(' ', this.width);
    return this.stylizeLine(left, content, right);
  }
Renders a blank line of text within the cell. Used for top and/or bottom padding.
@param drawRight - true if this method should render the right edge of the cell.
@param spanningCell - a number of if being called from a RowSpanCell. (how many rows below). otherwise undefined.
@returns {String}