var got dataUsageCache
	err = got.deserialize(&buf)
	if err != nil {
		t.Fatal(err)
	}
	if got.Info.LastUpdate.IsZero() {
		t.Error("lastupdate not set")
	}

	if !want.Info.LastUpdate.Equal(got.Info.LastUpdate) {
		t.Fatalf("deserialize LastUpdate mismatch\nwant: %+v\ngot:  %+v", want, got)
	}
	if len(want.Cache) != len(got.Cache) {

					case InsufficientReadQuorum, StorageErr:
						return true, nil
					}
					return false, err
				}
				err = d.deserialize(r)
				r.Close()
				return err != nil, nil
			case InsufficientReadQuorum, StorageErr:
				return true, nil
			}
			return false, err
		}
		err = d.deserialize(r)
		r.Close()
		return err != nil, nil
	}

	// Caches are read+written without locks,
	retries := 0

		if err == io.EOF {
			err = io.ErrUnexpectedEOF
		}
		if err != nil {
			cr.err = err
			return n, cr.err
		}
		if b == ';' { // separating character
			break
		}

		// Manually deserialize the size since AWS specified
		// the chunk size to be of variable width. In particular,
		// a size of 16 is encoded as `10` while a size of 64 KB
		// is `10000`.
		switch {
		case b >= '0' && b <= '9':

  tensorflow::core::CppShapeInferenceResult::HandleData handle_data;
  if (!handle_data.ParseFromArray(proto, proto_len)) {
    status->status =
        absl::InvalidArgumentError("Couldn't deserialize HandleData proto");
    return;
  }
  DCHECK(handle_data.is_set());

  tensorflow::mutex_lock l(graph->mu);
  tensorflow::shape_inference::InferenceContext* ic =

# Currently, there is no way to pass multiple cookies with the same name.
# The only way to pass multiple values for cookie params is to serialize them using

# Currently, there is no way to pass multiple cookies with the same name.
# The only way to pass multiple values for cookie params is to serialize them using

		return ""
	}
	return (*m)[key]
}

// Set a key, value pair.
func (m *MSS) Set(key, value string) {
	if m == nil {
		*m = mssPool.Get()
	}
	(*m)[key] = value
}

// UnmarshalMsg deserializes m from the provided byte slice and returns the
// remainder of bytes.
func (m *MSS) UnmarshalMsg(bts []byte) (o []byte, err error) {
	if m == nil {
		return bts, errors.New("MSS: UnmarshalMsg on nil pointer")
	}

```

</div>

Then go to the `/docs` UI, you will see that **FastAPI** is using these **models** to **document** the API, and it will use them to **serialize** and **validate** the data too.

<div class="screenshot">
<img src="/img/tutorial/sql-databases/image01.png">
</div>

## Update the App with Multiple Models { #update-the-app-with-multiple-models }

            raise ResponseValidationError(
                errors=errors,
                body=response_content,
                endpoint_ctx=ctx,
            )

        return field.serialize(
            value,
            include=include,
            exclude=exclude,
            by_alias=by_alias,
            exclude_unset=exclude_unset,
            exclude_defaults=exclude_defaults,

	if objectAPI == nil {
		return
	}

	// NB rebalance-start admin API is always coordinated from first pool's
	// first node. The following is required to serialize (the effects of)
	// concurrent rebalance-start commands.
	if ep := globalEndpoints[0].Endpoints[0]; !ep.IsLocal {
		for nodeIdx, proxyEp := range globalProxyEndpoints {
			if proxyEp.Host == ep.Host {