function

function twentyeleven_child_pagetemplates_body_classes( $wp_classes, $extra ){

      $classes = array();

      if( is_page_template( 'sidebar-page-left-in-one-column.php' ) ) :
      // correction for the Sidebar Template 'left sidebar on page in one-column layout'
        $classes[] = 'left-sidebar';
        $classes[] = 'two-column';
        $blacklist = array('one-column','content','right-sidebar','singular');
        // Filter the body classes
        foreach( $blacklist as $val ) {
          if (!in_array($val, $wp_classes)) : continue;
          else:
          foreach($wp_classes as $key => $value) {
            if ($value == $val) unset($wp_classes[$key]);
          }
          endif;
        }
      endif;

    return array_merge($wp_classes, (array) $extra, $classes );
    }

add_filter( 'body_class', 'twentyeleven_child_pagetemplates_body_classes', 20, 2 );