FluidXml\FluidInsertionHandler::insertStringSimple PHP Method

    protected function insertStringSimple($parent, $k, $v, $fn)
    {
        // The user has passed an element name and an element value:
        // [ 'element' => 'Element content' ]
        $el = $this->createElement($k, $v);
        $el = $fn($parent, $el);
        return [$el];
    }