* Add docs about [overriding the `operationId` for all the *path operations*](https://fastapi.tiangolo.com/advanced/path-operation-advanced-configuration/#using-the-path-operation-function-name-as-the-operationid) based on their function name. PR [#642](https://github.com/tiangolo/fastapi/pull/642) by [@SKalt](https://github.com/SKalt).

      int iterations = 100000;
      int nKeys = keys.size();
      int[] deltas = new int[nKeys];
      Operation[] operations = Operation.values();
      for (int i = 0; i < iterations; i++) {
        int keyIndex = random.nextInt(nKeys);
        String key = keys.get(keyIndex);
        Operation op = operations[random.nextInt(operations.length)];
        switch (op) {
          case ADD:
            {

Because the `SecurityScopes` will have all the scopes declared by dependants, you can use it to verify that a token has the required scopes in a central dependency function, and then declare different scope requirements in different *path operations*.

They will be checked independently for each *path operation*.

## Check it

It is the "**path operation decorator**".

///

You can also use the other operations:

* `@app.post()`
* `@app.put()`
* `@app.delete()`

And the more exotic ones:

* `@app.options()`
* `@app.head()`
* `@app.patch()`
* `@app.trace()`

/// tip

You are free to use each operation (HTTP method) as you wish.

## To `async` or not to `async`

As dependencies will also be called by **FastAPI** (the same as your *path operation functions*), the same rules apply while defining your functions.

You can use `async def` or normal `def`.

Swagger UI will handle it behind the scenes for you, but it needs this "redirect" helper.

///

### Create a *path operation* to test it

Now, to be able to test that everything works, create a *path operation*:

{* ../../docs_src/custom_docs_ui/tutorial001.py hl[36:38] *}

### Test it

<img src="/img/tutorial/additional-responses/image01.png">

## Combine predefined responses and custom ones

You might want to have some predefined responses that apply to many *path operations*, but you want to combine them with custom responses needed by each *path operation*.

For those cases, you can use the Python technique of "unpacking" a `dict` with `**dict_to_unpack`:

```Python
old_dict = {
    "old key": "old value",

public final class ConcurrentHashMultiset<E> extends AbstractMultiset<E> implements Serializable {

  /*
   * The ConcurrentHashMultiset's atomic operations are implemented primarily in terms of
   * AtomicInteger's atomic operations, with some help from ConcurrentMap's atomic operations on
   * creation and removal (including automatic removal of zeroes). If the modification of an

# Background Tasks

You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

 *
 * <ul>
 *   <li><b>Finite:</b> Many operations, such as {@link #length()} and {@link #read()}, will either
 *       block indefinitely or fail if the source creates an infinite reader.
 *   <li><b>Non-destructive:</b> A <i>destructive</i> reader will consume or otherwise alter the
 *       source as they are read from it. A source that provides such readers will not be reusable,