original_string: public function css_classes($css_classes) {
  
          // if argument is invalid
          if (!is_array($css_classes) || empty($css_classes) || array_keys($css_classes) != array_filter(array_keys($css_classes), function($value) { return in_array($value, array('list', 'list_item', 'anchor'), true); }))
  
              // stop execution
              trigger_error('Invalid argument. Method <strong>classes()</strong> accepts as argument an associative array with one or more of the following keys: <em>list, list_item, anchor</em>' , E_USER_ERROR);
  
          // merge values with the default ones
          $this->_properties['css_classes'] = array_merge($this->_properties['css_classes'], $css_classes);
  
      }
code: public function css_classes($css_classes) {
  
          // if argument is invalid
          if (!is_array($css_classes) || empty($css_classes) || array_keys($css_classes) != array_filter(array_keys($css_classes), function($value) { return in_array($value, array('list', 'list_item', 'anchor'), true); }))
  
              // stop execution
              trigger_error('Invalid argument. Method <strong>classes()</strong> accepts as argument an associative array with one or more of the following keys: <em>list, list_item, anchor</em>' , E_USER_ERROR);
  
          // merge values with the default ones
          $this->_properties['css_classes'] = array_merge($this->_properties['css_classes'], $css_classes);
  
      }
code_tokens: public function css_classes ( $ css_classes ) { // if argument is invalid if ( ! is_array ( $ css_classes ) || empty ( $ css_classes ) || array_keys ( $ css_classes ) != array_filter ( array_keys ( $ css_classes ) , function ( $ value ) { return in_array ( $ value , array ( 'list' , 'list_item' , 'anchor' ) , true ) ; } ) ) // stop execution trigger_error ( 'Invalid argument. Method <strong>classes()</strong> accepts as argument an associative array with one or more of the following keys: <em>list, list_item, anchor</em>' , E_USER_ERROR ) ; // merge values with the default ones $ this -> _properties [ 'css_classes' ] = array_merge ( $ this -> _properties [ 'css_classes' ] , $ css_classes ) ; }
docstring: Sets the CSS class names to be applied to the unorderd list, list item and anchors that make up the HTML markup
  of the pagination links.
  
  
  @param  array   $css_classes    An associative array with one or more or all of the following keys:
  
  -   <b>list</b>, for setting the CSS class name to be used for the unordered list (<kbd><ul></kbd>)
  -   <b>list_item</b>, for setting the CSS class name to be used for the list item (<kbd><li></kbd>)
  -   <b>anchor</b>, for setting the CSS class name to be used for the anchor (<kbd><a></kbd>)
  
  The default generated HTML markup looks like below:
  
  <code>
  <div class="Zebra_Pagination">
  <ul class="pagination">
  <li class="page-item">
  <a href="path/to/first/page/" class="page-link">1</a>
  </li>
  <li class="page-item">
  <a href="path/to/second/page/" class="page-link">2</a>
  </li>
  ...the other pages...
  </ul>
  </div>
  </code>
  
  Calling this method with the following argument...
  
  <code>
  $pagination->css_classes(array(
  'list'      =>  'foo',
  'list_item' =>  'bar',
  'anchor'    =>  'baz',
  ));
  </code>
  
  ...would result in the following markup:
  
  <code>
  <div class="Zebra_Pagination">
  <ul class="foo">
  <li class="bar">
  <a href="path/to/first/page/" class="baz">1</a>
  </li>
  <li class="bar">
  <a href="path/to/second/page/" class="baz">2</a>
  </li>
  ...the other pages...
  </ul>
  </div>
  </code>
  
  You can change only the CSS class names you want and the default CSS class names
  will be used for the other ones.
  
  Default values are:
  
  <code>
  $pagination->css_classes(array(
  'list'      =>  'pagination',
  'list_item' =>  'page-item',
  'anchor'    =>  'page-link',
  ));
  </code>
  
  These values make the resulting markup to be compatible with both the older version
  3 of Twitter Bootstrap as well as the new version 4.
  
  @return void
docstring_tokens: Sets the CSS class names to be applied to the unorderd list list item and anchors that make up the HTML markup of the pagination links .