* Generates tests of all methods on a {@code CharSource} given various inputs the source is
 * expected to contain.
 *
 * @author Colin Decker
 */
@AndroidIncompatible // TODO(b/230620681): Make this available (even though we won't run it).
public class CharSourceTester extends SourceSinkTester<CharSource, String, CharSourceFactory> {

---

## 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)

    theta_inputs[input_index] = thetaMinus.get();
    TF_RETURN_IF_ERROR(
        RunAndMaybeSum(ctx, forward, theta_inputs, f_outputs, use_function));
    AbstractTensorHandlePtr fMinus(f_outputs[0]);

    // Take Difference of both estimates: (f(theta + eps) - f(theta - eps)).
    TF_RETURN_IF_ERROR(
        ops::Sub(ctx, fPlus.get(), fMinus.get(), f_outputs, "sub_top"));
    AbstractTensorHandlePtr fDiff(f_outputs[0]);

		}
	}
	return
}

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

If you can choose a more recent version of Python for your project, you will be able to take advantage of that extra simplicity.

In all the docs there are examples compatible with each version of Python (when there's a difference).

// together in a multi-cluster mesh.
func NewCreateRemoteSecretCommand(ctx cli.Context) *cobra.Command {
	opts := RemoteSecretOptions{
		AuthType:         RemoteSecretAuthTypeBearerToken,
		AuthPluginConfig: make(map[string]string),
		Type:             SecretTypeRemote,
	}
	c := &cobra.Command{
		Use:   "create-remote-secret",
		Short: "Create a secret with credentials to allow Istio to access remote Kubernetes apiservers",

                    break;
                }
            }

            if (basedirExpr != null) {
                if (s.length() > basedirExpr.length()) {
                    // Take out basedir expression and the leading slash
                    s = chopLeadingFileSeparator(s.substring(basedirExpr.length()));
                } else {
                    s = ".";
                }
            }

    // together and this really shows the problem of constructing a sensible default configuration but
    // it's all encapsulated here so it appears normalized to the POM builder.

    // We are going to take the project packaging and find all plugin in the default lifecycle and create
    // fully populated Plugin objects, including executions with goals and default configuration taken
    // from the plugin.xml inside a plugin.
    //

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.