from fastapi import Depends, FastAPI, Security
from fastapi.security import SecurityScopes
from fastapi.testclient import TestClient

app = FastAPI()


def get_user(required_scopes: SecurityScopes):
    return "john", required_scopes.scopes


def get_user_override(required_scopes: SecurityScopes):
    return "alice", required_scopes.scopes


def get_data():
    return [1, 2, 3]


def get_data_override():

  <span style="background-color:#009485"><font color="#D3D7CF"> FastAPI </font></span>  Starting production server 🚀

             Searching for package file structure from directories
             with <font color="#3465A4">__init__.py</font> files
             Importing from <font color="#75507B">/home/user/code/</font><font color="#AD7FA8">awesomeapp</font>

For example, you could declare that something could be a `str` or `None`:

```python
from typing import Union


def say_hi(name: Union[str, None]):
        print(f"Hi {name}!")
```

`typing` also has a shortcut to declare that something could be `None`, with `Optional`.

Here's a tip from my very **subjective** point of view:

  @J2ktIncompatible
  @GwtIncompatible // used only from suite
  @AndroidIncompatible
  public static final class ImmutableDoubleArrayAsListGenerator extends TestDoubleListGenerator {
    @Override
    protected List<Double> create(Double[] elements) {
      return makeArray(elements).asList();
    }
  }

  @J2ktIncompatible
  @GwtIncompatible // used only from suite
  @AndroidIncompatible

    }

    /**
     * Deletes all documents that match the specified query from the specified index.
     *
     * @param searchEngineClient the search engine client to use for deletion
     * @param index the index name to delete documents from
     * @param queryBuilder the query to match documents for deletion
     * @return the number of documents that were deleted
     */

![ReDoc](https://fastapi.tiangolo.com/img/index/index-02-redoc-simple.png)

## Example upgrade

Now modify the file `main.py` to receive a body from a `PUT` request.

Declare the body using standard Python types, thanks to Pydantic.

```Python hl_lines="2  7-10 23-25"
from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float

  public void testIdentity() {
    for (CaseFormat from : CaseFormat.values()) {
      assertWithMessage("%s to %s", from, from).that(from.to(from, "foo")).isSameInstanceAs("foo");
      for (CaseFormat to : CaseFormat.values()) {
        assertWithMessage("%s to %s", from, to).that(from.to(to, "")).isEmpty();
        assertWithMessage("%s to %s", from, to).that(from.to(to, " ")).isEqualTo(" ");
      }
    }
  }

  <span style="background-color:#009485"><font color="#D3D7CF"> FastAPI </font></span>  Starting production server 🚀

             Searching for package file structure from directories
             with <font color="#3465A4">__init__.py</font> files
             Importing from <font color="#75507B">/home/user/code/</font><font color="#AD7FA8">awesomeapp</font>

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

app = FastAPI()


class UserBase(BaseModel):
    email: str


class UserCreate(UserBase):
    password: str


class UserDB(UserBase):
    hashed_password: str


class PetDB(BaseModel):
    name: str
    owner: UserDB


class PetOut(BaseModel):
    name: str
    owner: UserBase

**FastAPI** will take the Pydantic model from there, generate the JSON Schema, and put it in the correct place.

The correct place is:

* In the key `content`, that has as value another JSON object (`dict`) that contains:
    * A key with the media type, e.g. `application/json`, that contains as value another JSON object, that contains:
        * A key `schema`, that has as the value the JSON Schema from the model, here's the correct place.