app = FastAPI()


@app.get("/items/")
async def read_items():
    return [{"item_id": "Foo"}]


def use_route_names_as_operation_ids(app: FastAPI) -> None:
    """
    Simplify operation IDs so that generated API clients have simpler function
    names.

    Should be called only after all routes have been added.
    """
    for route in app.routes:
        if isinstance(route, APIRoute):

///

## Activate the Virtual Environment { #activate-the-virtual-environment }

Activate the new virtual environment so that any Python command you run or package you install uses it.

/// tip

Do this **every time** you start a **new terminal session** to work on the project.

///

//// tab | Linux, macOS

You shouldn't pin the version of `starlette`.

Different versions of **FastAPI** will use a specific newer version of Starlette.

So, you can just let **FastAPI** use the correct Starlette version.

## About Pydantic { #about-pydantic }

Pydantic includes the tests for **FastAPI** with its own tests, so new versions of Pydantic (above `1.0.0`) are always compatible with FastAPI.

Conversations in the chat systems are also not as easily searchable as in GitHub, so questions and answers might get lost in the conversation. And only the ones in GitHub count to become a [FastAPI Expert](fastapi-people.md#fastapi-experts){.internal-link target=_blank}, so you will most probably receive more attention in GitHub.

      BigInteger x4 = x.shiftLeft(2);
      // sqrt(x) < result + 0.5, so 4 * x < (result + 0.5)^2 * 4
      // (result + 0.5)^2 * 4 = (result^2 + result)*4 + 1
      assertThat(plusHalfSquared).isGreaterThan(x4);
      BigInteger minusHalfSquared = result.pow(2).subtract(result).shiftLeft(2).add(ONE);
      // sqrt(x) > result - 0.5, so 4 * x > (result - 0.5)^2 * 4
      // (result - 0.5)^2 * 4 = (result^2 - result)*4 + 1

setup_file() {
    bazel version  # Start the bazel server
}

# Do a bazel query specifically for the licenses checker. It searches for
# targets matching the provided query, which start with // or @ but not
# //tensorflow (so it looks for //third_party, //external, etc.), and then
# gathers the list of all packages (i.e. directories) which contain those
# targets.
license_query() {
 bazel cquery --experimental_cc_shared_library "$1" --keep_going \

    // in our test environment, which foils the purpose of this test, so we disable the logic for
    // our test by setting a static field. We are changing the field in the parallel version of FRQ
    // and each test creates its own one of those, so there is no test interference here.
    Class<?> sepFrqSystemLoaderC =

     *       cleared, we know that we're not executing inline any more
     * </ul>
     *
     * All the states where thread != currentThread are identical for our purposes, and so even
     * though it's racy, we don't care which of those values we get, so no need to synchronize.
     */
    @LazyInit @Nullable Thread thread;

    /** Only used by the thread associated with this object */
    @Nullable Runnable nextTask;

    // NPE on null listener, so we propagate that contract up into the add method as well.
    checkNotNull(runnable, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");

    // Lock while we check state. We must maintain the lock while adding the new pair so that
    // another thread can't run the list out from under us. We only add to the list if we have not

* „Python“ auswählen.
* Den Debugger mit der Option „`Python: Current File (Integrated Terminal)`“ ausführen.

Der Server wird dann mit Ihrem **FastAPI**-Code gestartet, an Ihren Haltepunkten angehalten, usw.

So könnte es aussehen:

<img src="/img/tutorial/debugging/image01.png">

---

Wenn Sie Pycharm verwenden, können Sie:

* Das Menü „Run“ öffnen.
* Die Option „Debug ...“ auswählen.