*/
internal sealed class Tags {
  /**
   * Returns a tags instance that maps [key] to [value]. If [value] is null, this returns a tags
   * instance that does not have any mapping for [key].
   */
  abstract fun <T : Any> plus(
    key: KClass<T>,
    value: T?,
  ): Tags

  abstract operator fun <T : Any> get(key: KClass<T>): T?
}

/** An empty tags. This is always the tail of a [LinkedTags] chain. */

        "price": 50.2,
        "tax": 10.5,
        "tags": [],
    }


def test_patch_all(client: TestClient):
    response = client.patch(
        "/items/foo",
        json={
            "name": "Fooz",
            "description": "Item description",
            "price": 3,
            "tax": 10.5,
            "tags": ["tag1", "tag2"],
        },
    )
    assert response.json() == {

    public void testMerge_tags() {
        SuggestItem item1 = createItemWithTags("text", "tag1", "tag2");
        SuggestItem item2 = createItemWithTags("text", "tag2", "tag3");

        SuggestItem merged = SuggestItemMerger.merge(item1, item2);

        String[] tags = merged.getTags();
        Set<String> tagSet = new HashSet<>(Arrays.asList(tags));

        assertEquals(3, tagSet.size());
        assertTrue(tagSet.contains("tag1"));

		return p
	}
	return ""
}

// Tags - a rule can either have tag under <filter></filter> or under
// <filter><and></and></filter>. This method returns all the tags from the
// rule in the format tag1=value1&tag2=value2
func (r Rule) Tags() string {
	if !r.Filter.Tag.IsEmpty() {
		return r.Filter.Tag.String()
	}
	if len(r.Filter.And.Tags) != 0 {
		var buf bytes.Buffer

	}
	return r.Filter.And.Prefix
}

// Tags - a rule can either have tag under <filter></filter> or under
// <filter><and></and></filter>. This method returns all the tags from the
// rule in the format tag1=value1&tag2=value2
func (r Rule) Tags() string {
	if !r.Filter.Tag.IsEmpty() {
		return r.Filter.Tag.String()
	}
	if len(r.Filter.And.Tags) != 0 {
		var buf bytes.Buffer

        .plus(Boolean::class, null)
    assertThat(tags).isEqualTo(EmptyTags)
    assertThat(tags.toString()).isEqualTo("{}")
  }

  @Test
  fun removeAbsentFromEmpty() {
    val tags = EmptyTags.plus(String::class, null)
    assertThat(tags).isEqualTo(EmptyTags)
    assertThat(tags.toString()).isEqualTo("{}")
  }

  @Test
  fun removeAbsentFromNonEmpty() {
    val tags =
      EmptyTags

	defer r.Unlock()
	// Search of tag key already exists in tags
	var updated bool
	for _, tag := range r.tags {
		if tag.Key == key {
			tag.Val = val
			updated = true
			break
		}
	}
	if !updated {
		// Append to the end of tags list
		r.tags = append(r.tags, KeyVal{key, val})
	}
	return r
}

// GetTags - returns the user defined tags
func (r *ReqInfo) GetTags() []KeyVal {
	if r == nil {

/// tip

You don't have to add metadata for all the tags that you use.

///

### Use your tags { #use-your-tags }

Use the `tags` parameter with your *path operations* (and `APIRouter`s) to assign them to different tags:

{* ../../docs_src/metadata/tutorial004_py310.py hl[21,26] *}

/// info

Read more about tags in [Path Operation Configuration](path-operation-configuration.md#tags).

///

from enum import Enum

from fastapi import FastAPI

app = FastAPI()


class Tags(Enum):
    items = "items"
    users = "users"


@app.get("/items/", tags=[Tags.items])
async def get_items():
    return ["Portal gun", "Plumbus"]


@app.get("/users/", tags=[Tags.users])
async def read_users():

)

// And - a tag to combine a prefix and multiple tags for replication configuration rule.
type And struct {
	XMLName xml.Name `xml:"And" json:"And"`
	Prefix  string   `xml:"Prefix,omitempty" json:"Prefix,omitempty"`
	Tags    []Tag    `xml:"Tag,omitempty" json:"Tag,omitempty"`
}

var errDuplicateTagKey = Errorf("Duplicate Tag Keys are not allowed")

// isEmpty returns true if Tags field is null
func (a And) isEmpty() bool {