public function getInjects(&$attr)
    {
        $inject = array(
            'before' => '',
            'between' => '',
            'after' => ''
        );

        if (! empty($attr['before'])) {
            $inject['before'] = $attr['before'];
            unset($attr['before']);
        }

        if (! empty($attr['between'])) {
            $inject['between'] = $attr['between'];
            unset($attr['between']);
        }

        if (! empty($attr['after'])) {
            $inject['after'] = $attr['after'];
            unset($attr['after']);
        }

        return $inject;
    }