for i, tt := range tests {
		err := readCRLF(tt.reader)
		if err != tt.expectedErr {
			t.Errorf("Test %d: Expected %s, got %s this", i+1, tt.expectedErr, err)
		}
	}
}

// Tests parsing hex number into its uint64 decimal equivalent.
func TestParseHexUint(t *testing.T) {
	type testCase struct {
		in      string
		want    uint64
		wantErr string
	}
	tests := []testCase{

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


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


@app.put("/items/{item_id}")
def update_item(item_id: int, item: Item):
    return {"item_name": item.name, "item_id": item_id}
```

Remember I told you before that `Annotated` can be used to add metadata to your parameters in the [Python Types Intro](../python-types.md#type-hints-with-metadata-annotations){.internal-link target=_blank}?

Now it's the time to use it with FastAPI. 🚀

We had this type annotation:

//// tab | Python 3.10+

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

	if err != nil {
		return err
	}
	return nil
}

// deserialize the supplied byte slice into the cache.
func (d *dataUsageCache) deserialize(r io.Reader) error {
	var b [1]byte
	n, _ := r.Read(b[:])
	if n != 1 {
		return io.ErrUnexpectedEOF
	}
	ver := int(b[0])
	switch ver {
	case dataUsageCacheVerV1:
		return errors.New("cache version deprecated (will autoupdate)")

				if isDeprecated(n.Doc) {
					mark(n.Name)
				}
				return true // recurse into struct or interface type
			case *ast.StructType:
				return true // recurse into fields
			case *ast.InterfaceType:
				return true // recurse into methods
			case *ast.FieldList:
				return true // recurse into fields
			case *ast.ValueSpec:
				if isDeprecated(n.Doc) {
					for _, id := range n.Names {

        // with the parameters
        // <li>1. KDFCounterParameters(ki, null, "Label || 0x00 || Context || [L]_2]", 8);

        // all fixed inputs go into the suffix:
        // + label
        System.arraycopy(label, 0, suffix, 0, label.length);
        // + 1 byte 0x00
        // + context
        System.arraycopy(context, 0, suffix, label.length + 1, context.length);

		SlowThreshold:             200 * time.Millisecond,
		LogLevel:                  Warn,
		IgnoreRecordNotFoundError: false,
		Colorful:                  true,
	})
	// Recorder logger records running SQL into a recorder instance
	Recorder = traceRecorder{Interface: Default, BeginAt: time.Now()}

	// RecorderParamsFilter defaults to no-op, allows to be run-over by a different implementation

////

## Títulos { #headings }

//// tab | Teste

### Desenvolver uma aplicação web - um tutorial { #develop-a-webapp-a-tutorial }

Olá.

### Anotações de tipo e -anotações { #type-hints-and-annotations }

Olá novamente.

### Super- e subclasses { #super-and-subclasses }

Olá novamente.

////

//// tab | Informações

You can use OAuth2 scopes directly with **FastAPI**, they are integrated to work seamlessly.

This would allow you to have a more fine-grained permission system, following the OAuth2 standard, integrated into your OpenAPI application (and the API docs).

    }

    // Helper methods to write data to byte arrays for testing read methods
    private void writeInt2(int val, byte[] dst, int dstIndex) {
        dst[dstIndex] = (byte) val;
        dst[dstIndex + 1] = (byte) (val >> 8);
    }

    private void writeInt4(int val, byte[] dst, int dstIndex) {
        dst[dstIndex] = (byte) val;
        dst[dstIndex + 1] = (byte) (val >> 8);