///

FastAPI will now:

* **Validate** the data making sure that the max length is 50 characters
* Show a **clear error** for the client when the data is not valid

    .build();
```

Client Authentication
---------------------

The above scenario is representative of most TLS set ups: the client uses certificates to validate
the identity of a server. The converse is also possible. Here we create a server that authenticates
a client and a client that authenticates a server.

```java

  }
  if (remote) {
    TFE_OpSetDevice(matmul, task1_name, status);
    ASSERT_EQ(TF_GetCode(status), TF_OK) << TF_Message(status);
  } else if (!async) {
    // Set the local device to CPU to easily validate mirroring
    string cpu_device_name;
    ASSERT_TRUE(GetDeviceName(ctx, &cpu_device_name, "CPU"));
    TFE_OpSetDevice(matmul, cpu_device_name.c_str(), status);

			if err != nil {
				rpt.SetStatus(bucket, fileName, err)
				continue
			}
			// Validate the received bucket policy document
			if err = bucketLifecycle.Validate(rcfg); err != nil {
				rpt.SetStatus(bucket, fileName, err)
				continue
			}

			// Validate the transition storage ARNs
			if err = validateTransitionTier(bucketLifecycle); err != nil {
				rpt.SetStatus(bucket, fileName, err)

			[]byte("10000;chunk-signature=ad80c730a21e5b8d04586a2213dd63b9a0e99e0e2307b0ade35a65485a288648    \t \n"),
			[]byte("10000"),
			[]byte("ad80c730a21e5b8d04586a2213dd63b9a0e99e0e2307b0ade35a65485a288648"),
		},
	}
	// Validate chunk extension removal.
	for i, tt := range tests {
		// Extract chunk size and chunk signature after parsing a standard chunk-extension format.
		hexChunkSize, hexChunkSignature := parseS3ChunkExtension(tt.buf)

	if err != nil {
		apiErr := errorCodes.ToAPIErr(ErrMalformedXML)
		apiErr.Description = err.Error()
		writeErrorResponse(ctx, w, apiErr, r.URL)
		return
	}
	// validate the request
	if err := rreq.validate(ctx, objectAPI); err != nil {
		apiErr := errorCodes.ToAPIErr(ErrMalformedXML)
		apiErr.Description = err.Error()
		writeErrorResponse(ctx, w, apiErr, r.URL)
		return
	}

	defer env.LockSetEnv()()

	// Disable merging env values with config for validation.
	env.SetEnvOff()

	// Enable env values to validate KMS.
	defer env.SetEnvOn()
	if subSys != "" {
		return validateSubSysConfig(ctx, s, subSys, objAPI)
	}

	// No sub-system passed. Validate all of them.
	for _, ss := range config.SubSystems.ToSlice() {
		if err := validateSubSysConfig(ctx, s, ss, objAPI); err != nil {
			return err

	resp, err := httpClient.Do(req)
	if err != nil {
		return err
	}
	xhttp.DrainBody(resp.Body)

	return nil
}

// connect to list of endpoints and load all Erasure disk formats, validate the formats are correct
// and are in quorum, if no formats are found attempt to initialize all of them for the first
// time. additionally make sure to close all the disks used in this attempt.

      inverse.delegate.remove(entry.getValue());
      /*
       * Remove the mapping in inverse before removing from esDelegate because
       * if entry is part of esDelegate, entry might be invalidated after the
       * mapping is removed from esDelegate.
       */
      esDelegate.remove(entry);
      return true;
    }

    @Override
    public Iterator<Entry<K, V>> iterator() {

...and declare its type as the model you created, `Item`.

## Results

With just that Python type declaration, **FastAPI** will:

* Read the body of the request as JSON.
* Convert the corresponding types (if needed).
* Validate the data.
    * If the data is invalid, it will return a nice and clear error, indicating exactly where and what was the incorrect data.
* Give you the received data in the parameter `item`.