protected static function getDefaultNormalizersMap()
    {
        return array(
            self::FIELD_UNIQUE_ID       =>   self::FIELD_UNIQUE_ID,
            self::FIELD_USERNAME        =>   self::FIELD_USERNAME,
            self::FIELD_FIRST_NAME      =>   self::FIELD_FIRST_NAME,
            self::FIELD_LAST_NAME       =>   self::FIELD_LAST_NAME,
            self::FIELD_FULL_NAME       =>   self::FIELD_FULL_NAME,
            self::FIELD_EMAIL           =>   self::FIELD_EMAIL,
            self::FIELD_DESCRIPTION     =>   self::FIELD_DESCRIPTION,
            self::FIELD_LOCATION        =>   self::FIELD_LOCATION,
            self::FIELD_PROFILE_URL     =>   self::FIELD_PROFILE_URL,
            self::FIELD_IMAGE_URL       =>   self::FIELD_IMAGE_URL,
            self::FIELD_WEBSITES        =>   self::FIELD_WEBSITES,
            self::FIELD_VERIFIED_EMAIL  =>   self::FIELD_VERIFIED_EMAIL,
            self::FIELD_EXTRA           =>   self::FIELD_EXTRA,
        );
    }