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`.

about: Use Stack Overflow instead
title: "\U0001F649"
labels: ''
assignees: ''

---

🛑 𝙎𝙏𝙊𝙋

This issue tracker is not the place for questions!

If you want to ask how to do something, or to understand why something isn't working the way you expect it to, use Stack Overflow. https://stackoverflow.com/questions/tagged/okhttp

      Stopwatch s = Stopwatch.createStarted();
      // here is where you would do something
      total += s.elapsed(NANOSECONDS);
    }
    return total;
  }

  @Benchmark
  long manual(int reps) {
    long total = 0;
    for (int i = 0; i < reps; i++) {
      long start = System.nanoTime();
      // here is where you would do something
      total += System.nanoTime() - start;
    }
    return total;
  }

    model_config = {
        "json_schema_extra": {
            "x-something-internal": {"level": 4},
        }
    }


@app.get("/foo", response_model=Item)
def foo():
    return {"name": "Foo item"}


client = TestClient(app)


item_schema = {
    "title": "Item",
    "required": ["name"],
    "type": "object",
    "x-something-internal": {
        "level": 4,
    },
    "properties": {

      Stopwatch s = Stopwatch.createStarted();
      // here is where you would do something
      total += s.elapsed(NANOSECONDS);
    }
    return total;
  }

  @Benchmark
  long manual(int reps) {
    long total = 0;
    for (int i = 0; i < reps; i++) {
      long start = System.nanoTime();
      // here is where you would do something
      total += System.nanoTime() - start;
    }
    return total;
  }

        String details = testableJob.testFormatDetails(events);

        assertNotNull(details);
        assertTrue(details.contains("Total: 1 event(s)"));
        assertTrue(details.contains("ERROR"));
        assertTrue(details.contains("org.codelibs.fess.TestClass"));
        assertTrue(details.contains("Something went wrong"));
    }

    @Test

            "age": "70",
            "tags": ["plumbus", "citadel"],
            "with": "something",
        },
    )
    assert response.status_code == 200, response.text
    assert response.json() == {
        "username": "Rick",
        "lastname": "Sanchez",
        "age": 70,
        "tags": ["plumbus", "citadel"],
        "with": "something",
    }


def test_defaults():

If you check, the function is decorated with an `@asynccontextmanager`.

That converts the function into something called an "**async context manager**".

{* ../../docs_src/events/tutorial003_py310.py hl[1,13] *}

A **context manager** in Python is something that you can use in a `with` statement, for example, `open()` can be used as a context manager:

```Python
with open("file.txt") as file:

# JSON Compatible Encoder { #json-compatible-encoder }

There are some cases where you might need to convert a data type (like a Pydantic model) to something compatible with JSON (like a `dict`, `list`, etc).

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder` { #using-the-jsonable-encoder }

Asynchronous code just means that the language 💬 has a way to tell the computer / program 🤖 that at some point in the code, it 🤖 will have to wait for *something else* to finish somewhere else. Let's say that *something else* is called "slow-file" 📝.

So, during that time, the computer can go and do some other work, while "slow-file" 📝 finishes.