def get_current_user(oauth_header: Optional[str] = Security(reusable_oauth2)):
    if oauth_header is None:
        return None
    user = User(username=oauth_header)
    return user


@app.post("/login")
def login(form_data: OAuth2PasswordRequestFormStrict = Depends()):
    return form_data


@app.get("/users/me")
def read_users_me(current_user: Optional[User] = Depends(get_current_user)):

from typing import Optional

from dirty_equals import IsDict
from fastapi import APIRouter, FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel, HttpUrl

app = FastAPI()


class Invoice(BaseModel):
    id: str
    title: Optional[str] = None
    customer: str
    total: float


class InvoiceEvent(BaseModel):
    description: str
    paid: bool


class InvoiceEventReceived(BaseModel):

@ElementTypesAreNonnullByDefault
public final class NetworkBuilder<N, E> extends AbstractGraphBuilder<N> {
  boolean allowsParallelEdges = false;
  ElementOrder<? super E> edgeOrder = ElementOrder.insertion();
  Optional<Integer> expectedEdgeCount = Optional.absent();

  /** Creates a new instance with the specified edge directionality. */
  private NetworkBuilder(boolean directed) {
    super(directed);
  }

            String groupId,
            String artifactId,
            VersionRange versionRange,
            String type,
            String classifier,
            String scope,
            boolean optional);

    Artifact createDependencyArtifact(
            String groupId,
            String artifactId,
            VersionRange versionRange,
            String type,
            String classifier,

So:

```Python
q: Union[str, None] = Query(default=None)
```

...makes the parameter optional, with a default value of `None`, the same as:

```Python
q: Union[str, None] = None
```

And in Python 3.10 and above:

```Python
q: str | None = Query(default=None)
```

...makes the parameter optional, with a default value of `None`, the same as:

```Python
q: str | None = None
```

from typing import Optional, Union

from dirty_equals import IsDict
from fastapi import FastAPI
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: Optional[str] = None


class ExtendedItem(Item):
    age: int


@app.post("/items/")
def save_union_different_body(item: Union[ExtendedItem, Item]):
    return {"item": item}

    }

    @Override
    public Path getRootDirectory() {
        return project.getRootDirectory();
    }

    @Override
    public Optional<Project> getParent() {
        MavenProject parent = project.getParent();
        return Optional.ofNullable(session.getProject(parent));
    }

    @Nonnull
    private DependencyCoordinates toDependency(org.apache.maven.api.model.Dependency dependency) {

from contextvars import ContextVar
from typing import Any, Awaitable, Callable, Dict, Optional

from fastapi import Depends, FastAPI, Request, Response
from fastapi.testclient import TestClient

legacy_request_state_context_var: ContextVar[Optional[Dict[str, Any]]] = ContextVar(
    "legacy_request_state_context_var", default=None
)

app = FastAPI()


async def set_up_request_state_dependency():
    request_state = {"user": "deadpond"}

#ifndef TENSORFLOW_C_EAGER_IMMEDIATE_EXECUTION_OPERATION_H_
#define TENSORFLOW_C_EAGER_IMMEDIATE_EXECUTION_OPERATION_H_

#include <memory>

#include "absl/types/optional.h"
#include "absl/types/span.h"
#include "tensorflow/c/eager/abstract_operation.h"
#include "tensorflow/c/eager/immediate_execution_tensor_handle.h"
#include "tensorflow/c/tensor_interface.h"

            </Export-Package>
            <Import-Package>
              com.google.common.util.concurrent.internal,
              javax.annotation;resolution:=optional,
              javax.crypto.*;resolution:=optional,
              sun.misc.*;resolution:=optional
            </Import-Package>
            <Bundle-DocURL>https://github.com/google/guava/</Bundle-DocURL>
          </instructions>
        </configuration>