---

## Install FastAPI

The first step is to install FastAPI.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then **install FastAPI**:

<div class="termy">

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

func (b *bufPool) Get() []byte {
	bufp := b.pool.Get().(*[]byte)
	return (*bufp)[:b.sz]
}

func newBufPool(sz int) httputil.BufferPool {
	return &bufPool{sz: sz, pool: sync.Pool{
		New: func() interface{} {
			buf := make([]byte, sz)
			return &buf
		},
	}}
}

// ServeHTTP forwards HTTP traffic using the configured transport
func (f *Forwarder) ServeHTTP(w http.ResponseWriter, inReq *http.Request) {
	outReq := new(http.Request)

		}
	}
	return
}

func handleAndGetXdsConfigs(clientConfig *xdsstatus.ClientConfig) []*xdsstatus.ClientConfig_GenericXdsConfig {
	configs := make([]*xdsstatus.ClientConfig_GenericXdsConfig, 0)
	if clientConfig.GetGenericXdsConfigs() != nil {
		configs = clientConfig.GetGenericXdsConfigs()
		return configs
	}

This way, its schema will show up in the API docs user interface:

<img src="/img/tutorial/dataclasses/image01.png">

## Dataclasses in Nested Data Structures

You can also combine `dataclasses` with other type annotations to make nested data structures.

In some cases, you might still have to use Pydantic's version of `dataclasses`. For example, if you have errors with the automatically generated API documentation.

		}
		if port == 0 {
			port = 8021 // Default FTP port, since no port was given.
		}
	}

	// If no TLS certs were provided, server is running in TLS for S3 API
	// we automatically make FTP also run under TLS mode.
	if globalIsTLS && tlsPrivateKey == "" && tlsPublicCert == "" {
		tlsPrivateKey = getPrivateKeyFile()
		tlsPublicCert = getPublicCertFile()
	}

## Dispatch

For synchronous calls, you bring your own thread and are responsible for managing how many simultaneous requests you make. Too many simultaneous connections wastes resources; too few harms latency.

      return x.longValue();
    } else if (exponent > MAX_EXPONENT) {
      return x.signum() * POSITIVE_INFINITY;
    }

    /*
     * We need the top SIGNIFICAND_BITS + 1 bits, including the "implicit" one bit. To make rounding
     * easier, we pick out the top SIGNIFICAND_BITS + 2 bits, so we have one to help us round up or
     * down. twiceSignifFloor will contain the top SIGNIFICAND_BITS + 2 bits, and signifFloor the

template "minio.name" . }} {{- end }} minio/templates/post-install-create-bucket-job.yaml {{- if .Values.buckets }} apiVersion: batch/v1 kind: Job metadata: name: {{ template "minio.fullname" . }}-make-bucket-job namespace: {{ .Release.Namespace | quote }} labels: app: {{ template "minio.name" . }}-make-bucket-job chart: {{ template "minio.chart" . }} release: {{ .Release.Name }} heritage: {{ .Release.Service }} annotations: "helm.sh/hook": post-install,post-upgrade "helm.sh/hook-delete-policy": ...

    // We use this somewhat weird pattern with an enum for each assertion we want to make as a way
    // of dealing with the fact that one of the assertions is @GwtIncompatible but we don't want to
    // have to have duplicate @GwtIncompatible test methods just to make that assertion.
    for (AssertFailsToDecodeStrategy strategy : AssertFailsToDecodeStrategy.values()) {

   * AnnotatedElement}, which {@code TypeVariable} began to extend only in Java 8. Those methods
   * refer only to types present in Java 7, so we could implement them in {@code TypeVariableImpl}
   * today. (We could probably then make {@code TypeVariableImpl} implement {@code AnnotatedElement}
   * so that we get partial compile-time checking.)
   *
   * <p>This workaround should be removed at a distant future time when we no longer support Java