protected function parseData()
    {
        $values = [];
        foreach ($this->parts['data'] as $key => $data) {
            foreach ($data as $value) {
                if (!is_array($value)) {
                    $value = [$value];
                }

                foreach ($value as $insertValue) {
                    $values[$key][] = $this->getManager()->getAdapter()->quote($insertValue);
                }
            }
        }
        foreach ($values as &$value) {
            $value = "(" . implode(", ", $value) . ")";
        }

        return ' VALUES ' . implode(', ', $values);
    }