original_string: public function container_start($classes = null, $id = null) {
          $this->opencontainers->push('container', html_writer::end_tag('div'));
          return html_writer::start_tag('div', array('id' => $id,
                  'class' => renderer_base::prepare_classes($classes)));
      }
code: public function container_start($classes = null, $id = null) {
          $this->opencontainers->push('container', html_writer::end_tag('div'));
          return html_writer::start_tag('div', array('id' => $id,
                  'class' => renderer_base::prepare_classes($classes)));
      }
code_tokens: public function container_start ( $ classes = null , $ id = null ) { $ this -> opencontainers -> push ( 'container' , html_writer :: end_tag ( 'div' ) ) ; return html_writer :: start_tag ( 'div' , array ( 'id' => $ id , 'class' => renderer_base :: prepare_classes ( $ classes ) ) ) ; }
docstring: Outputs the opening section of a container.
  
  @param string $classes A space-separated list of CSS classes
  @param string $id An optional ID
  @return string the HTML to output.
docstring_tokens: Outputs the opening section of a container .