@Override
            public String[] getRoles(LdapUser user, String baseDn, String accountFilter, String groupFilter, Consumer<String[]> callback) {
                // Return roles with duplicates
                String[] roles = new String[] { "role1", "role2", "role1", "Uuser", "role2" };
                callback.accept(roles);
                return roles;
            }

            @Override

* `frozenset`:
    * In requests and responses, treated the same as a `set`:
        * In requests, a list will be read, eliminating duplicates and converting it to a `set`.
        * In responses, the `set` will be converted to a `list`.
        * The generated schema will specify that the `set` values are unique (using JSON Schema's `uniqueItems`).
* `bytes`:

Then we can declare `tags` as a set of strings:

{* ../../docs_src/body_nested_models/tutorial003_py310.py hl[12] *}

With this, even if you receive a request with duplicate data, it will be converted to a set of unique items.

And whenever you output that data, even if the source had duplicates, it will be output as a set of unique items.

And it will be annotated / documented accordingly too.

## Nested Models { #nested-models }

        Map<String, String> queryMap = facetQueryView.getQueryMap();

        // Should not duplicate existing pdf query
        assertEquals("filetype:pdf", queryMap.get("existing_pdf"));
        // Should add doc since it's not present
        assertEquals("filetype:doc", queryMap.get("DOC"));

        // Check no duplicate queries added to FacetInfo
        List<String> addedQueries = testFacetInfo.getAddedQueries();

			success: false,
		},
		// no duplicates, shall be parsed properly.
		{

        assertNotNull(invalidKeywords);
        assertEquals(0, invalidKeywords.size());
    }

    @Test
    public void testGetKeywordsWithDuplicates() {
        // Test that duplicates are removed
        String query = "test test query";
        String[] fields = { "content" };
        List<String> keywords = SuggestUtil.getKeywords(query, fields);
        assertNotNull(keywords);

        SuggestItem.Kind[] result = SuggestItem.concatKinds(kinds1, kinds2);

        assertNotNull(result);
        assertEquals(2, result.length); // Should not have duplicates
        assertTrue(Arrays.asList(result).contains(SuggestItem.Kind.QUERY));
        assertTrue(Arrays.asList(result).contains(SuggestItem.Kind.DOCUMENT));
    }

    @Test
    public void testEmptySource() {

	if v == nil {
		bugLogIf(ctx, errInvalidArgument)
		return errInvalidArgument
	}

	nv := make(textproto.MIMEHeader, len(v))
	for k, kv := range v {
		// Canonicalize all headers, to remove any duplicates.
		nv[http.CanonicalHeaderKey(k)] = kv
	}

	// Save all supported headers.
	for _, supportedHeader := range supportedHeaders {
		value, ok := nv[http.CanonicalHeaderKey(supportedHeader)]
		if ok {

				break
			}
		}

		if requestedVersions > 0 && requestedVersions == nVersions {
			merged = append(merged, versions[0]...)
			break
		}
	}

	// Sanity check. Enable if duplicates show up.
	if false {
		found := make(map[[16]byte]struct{})
		for _, ver := range merged {
			if _, ok := found[ver.header.VersionID]; ok {
				panic("found dupe")
			}

		for _, user := range q.Users {
			lookupRes, actualGroups, _ := sys.LDAPConfig.GetValidatedDNWithGroups(user)
			if lookupRes != nil {
				groupSet := set.CreateStringSet(actualGroups...)

				// duplicates can be overwritten, fetched groups should be identical.
				cleanQ.Users[lookupRes.NormDN] = groupSet
			}
			// Search for non-normalized DN as well for backward compatibility.
			if _, ok := cleanQ.Users[user]; !ok {