AdamWathan\Form\Elements\Select::renderOptions PHP Method

    protected function renderOptions()
    {
        list($values, $labels) = $this->splitKeysAndValues($this->options);
        $tags = array_map(function ($value, $label) {
            if (is_array($label)) {
                return $this->renderOptGroup($value, $label);
            }
            return $this->renderOption($value, $label);
        }, $values, $labels);
        return implode($tags);
    }