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':

    }

    /**
     * Serialize the inbound Model instance to a StringWriter, perform the regex replacement to resolve
     * POM expressions, then re-parse into the resolved Model instance.
     * <p>
     * <b>NOTE:</b> This will result in a different instance of Model being returned!!!
     *
     * @param model The inbound Model instance, to serialize and reference for expression resolution

		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")
	}

	log.SetPrefix("go_android_exec: ")
	exitCode, err := runMain()
	if err != nil {
		log.Fatal(err)
	}
	os.Exit(exitCode)
}

func runMain() (int, error) {
	// Concurrent use of adb is flaky, so serialize adb commands.
	// See https://github.com/golang/go/issues/23795 or
	// https://issuetracker.google.com/issues/73230216.
	lockPath := filepath.Join(os.TempDir(), "go_android_exec-adb-lock")

```

</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 }

	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 {

            )
        except ValidationError as exc:
            return None, _regenerate_error_with_loc(
                errors=exc.errors(include_url=False), loc_prefix=loc
            )

    def serialize(
        self,
        value: Any,
        *,
        mode: Literal["json", "python"] = "json",
        include: Union[IncEx, None] = None,
        exclude: Union[IncEx, None] = None,

### Existing object replication