code: public function setPadding($padding)
      {
          list($top, $right, $bottom, $left) = $this->paddingStringToArray($padding);
          $this->padding['top'] = $top;
          $this->padding['right'] = $right;
          $this->padding['bottom'] = $bottom;
          $this->padding['left'] = $left;
      }
docs: Set padding : format top right bottom left
  ex: 0 10 0 10.
  
  @param string $padding