public function setBirthdate($birthdate)
    {
        $date = DateTime::createFromFormat('Y-m-d', $birthdate);

        $this->data->birthdate_day = $date->format('d');
        $this->data->birthdate_month = $date->format('m');
        $this->data->birthdate_year = $date->format('Y');

        return $this;
    }