</div>

## Forbid Extra Headers

In some special use cases (probably not very common), you might want to **restrict** the headers that you want to receive.

You can use Pydantic's model configuration to `forbid` any `extra` fields:

//// tab | Python 3.10+

```Python hl_lines="10"
{!> ../../docs_src/header_param_models/tutorial002_an_py310.py!}
```

////

//// tab | Python 3.9+

```Python hl_lines="10"

      return arbitraryConstantInstanceOrNull(type);
    }
  }

  private static <T> @Nullable T arbitraryConstantInstanceOrNull(Class<T> type) {
    Field[] fields = type.getDeclaredFields();
    Arrays.sort(fields, BY_FIELD_NAME);
    for (Field field : fields) {
      if (Modifier.isPublic(field.getModifiers())
          && Modifier.isStatic(field.getModifiers())
          && Modifier.isFinal(field.getModifiers())) {

                                    </la:info>
                                    <la:errors/>
                                </div>
                                    <%-- Form Fields --%>
                                <table class="table table-bordered">
                                    <tbody>
                                    <c:if test="${id != null}">
                                        <tr>

      return arbitraryConstantInstanceOrNull(type);
    }
  }

  private static <T> @Nullable T arbitraryConstantInstanceOrNull(Class<T> type) {
    Field[] fields = type.getDeclaredFields();
    Arrays.sort(fields, BY_FIELD_NAME);
    for (Field field : fields) {
      if (Modifier.isPublic(field.getModifiers())
          && Modifier.isStatic(field.getModifiers())
          && Modifier.isFinal(field.getModifiers())) {

             * necessarily populated with header data because they're not writing
             * the header, only their body. But for whatever reason one might wish
             * to populate fields if the writeXxx operation needs this header data
             * for whatever reason. I copy over the uid here so it appears correct
             * in logging output. Logging of andx segments of messages inadvertantly

                                    </la:info>
                                    <la:errors/>
                                </div>
                                    <%-- Form Fields --%>
                                <table class="table table-bordered">
                                    <tbody>
                                    <tr>

                                    </la:info>
                                    <la:errors/>
                                </div>
                                    <%-- Form Fields --%>
                                <table class="table table-bordered">
                                    <tbody>
                                    <tr>

	Region       string           `json:"-"`
	Owner        bool             `json:"-"`
	AuthType     string           `json:"-"`
	tags         []KeyVal         // Any additional info not accommodated by above fields
	sync.RWMutex
}

// NewReqInfo :
func NewReqInfo(remoteHost, userAgent, deploymentID, requestID, api, bucket, object string) *ReqInfo {
	return &ReqInfo{
		RemoteHost:   remoteHost,
		UserAgent:    userAgent,

                                    </la:info>
                                    <la:errors/>
                                </div>
                                    <%-- Form Fields --%>
                                <table class="table table-bordered">
                                    <tbody>
                                    <tr>

        });
    }

    public DictionaryFile<? extends DictionaryItem>[] getDictionaryFiles() {
        try (CurlResponse response = ComponentUtil.getCurlHelper().get("/_configsync/file").param("fields", "path,@timestamp")
                .param("size", ComponentUtil.getFessConfig().getPageDictionaryMaxFetchSize()).execute()) {
            final Map<String, Object> contentMap = response.getContent(OpenSearchCurl.jsonParser());