s.writeErrorResponse(w, err)
		return false
	}

	diskID := r.Form.Get(storageRESTDiskID)
	if diskID == "" {
		// Request sent empty disk-id, we allow the request
		// as the peer might be coming up and trying to read format.json
		// or create format.json
		return true
	}

	storedDiskID, err := s.getStorage().GetDiskID()
	if err != nil {
		s.writeErrorResponse(w, err)
		return false
	}

map[string]interface{}
</pre>

<p>
The number of map elements is called its length.
For a map <code>m</code>, it can be discovered using the
built-in function <a href="#Length_and_capacity"><code>len</code></a>
and may change during execution. Elements may be added during execution
using <a href="#Assignment_statements">assignments</a> and retrieved with
<a href="#Index_expressions">index expressions</a>; they may be removed with the

<div class="termy">

```console
$ pip install "uvicorn[standard]"

---> 100%
```

</div>

## 🖼

### ✍ ⚫️

* ✍ 📁 `main.py` ⏮️:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")

```console
$ pip install "uvicorn[standard]"

---> 100%
```

</div>

## דוגמא

### צרו אותה

-   צרו קובץ בשם `main.py` עם:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")

     * past them.)
     *
     * We could consider "lying" and omitting @CheckNotNull from all these fields. Normally, I'm not
     * a fan of that: What if we someday implement (presumably to be enabled during tests only)
     * bytecode rewriting that checks for any null value that passes through an API with a
     * known-non-null type? But that particular problem might not arise here, since we're not

```console
$ pip install "uvicorn[standard]"

---> 100%
```

</div>

## Beispiel

### Erstellung

* Erstellen Sie eine Datei `main.py` mit:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")

Führen Sie nun `uvicorn` aus, indem Sie das Modul `app.main` und die Variable `app` verwenden:

<div class="termy">

```console
$ uvicorn app.main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
```

</div>

und öffnen Sie die Dokumentation unter <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

```console
$ pip install uvicorn[standard]

---> 100%
```

</div>

## Esempio

### Crea un file

* Crea un file `main.py` con:

```Python
from fastapi import FastAPI
from typing import Optional

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: str = Optional[None]):

 * {@link Collections#singleton(Object)} and <a
 * href="https://docs.oracle.com/javase/9/docs/api/java/util/Set.html#immutable">{@code Set.of}</a>,
 * we recommend using <i>these</i> classes instead for this reason (as well as for consistency).
 *
 * <h4>Creation</h4>
 *
 * <p>Except for logically "abstract" types like {@code ImmutableCollection} itself, each {@code

			if err != tc.expectedParsingErr {
				t.Fatalf("%d: Expected %v during parsing but got %v", i+1, tc.expectedParsingErr, err)
			}
			if tc.expectedParsingErr != nil {
				// We already expect a parsing error,
				// no need to continue this test.
				return
			}
			err = lc.Validate(tc.lr)
			if err != tc.expectedValidationErr {
				t.Fatalf("%d: Expected %v during validation but got %v", i+1, tc.expectedValidationErr, err)
			}