CMB2::box_classes PHP Method

    public function box_classes()
    {
        $classes = array('cmb2-wrap', 'form-table');
        $cb = $this->prop('classes_cb');
        // Use the callback to fetch classes.
        if (is_callable($cb) && ($added_classes = call_user_func($cb, $this))) {
            $added_classes = is_array($added_classes) ? $added_classes : array($added_classes);
            $classes = array_merge($classes, $added_classes);
        }
        if ($added_classes = $this->prop('classes')) {
            $added_classes = is_array($added_classes) ? $added_classes : array($added_classes);
            $classes = array_merge($classes, $added_classes);
        }
        /**
         * Globally filter box wrap classes
         *
         * @since 2.2.2
         *
         * @param string $classes Array of classes for the cmb2-wrap.
         * @param CMB2   $cmb     This CMB2 object.
         */
        $classes = apply_filters('cmb2_wrap_classes', $classes, $this);
        // Clean up.
        $classes = array_map('strip_tags', array_filter($classes));
        // Make a string.
        return implode(' ', $classes);
    }