code: public function setSorting($strSortBy, $strDirection = 'ASC')
      {
          $this->strSortBy        = $strSortBy;
          $this->strSortDirection = ($strDirection == 'DESC') ? 'DESC' : 'ASC';
  
          return $this;
      }
docs: Set sorting to an attribute or system column optionally in the given direction.
  
  @param string $strSortBy    The name of the attribute or system column to be used for sorting.
  
  @param string $strDirection The direction, either ASC or DESC (optional).
  
  @return ItemList