@Nonnull
    public static Function<String, String> prefix(String prefix, Function<String, String> cb) {
        return s -> {
            String v = null;
            if (s.startsWith(prefix)) {
                v = cb.apply(s.substring(prefix.length()));
            }
            return v;
        };
    }

    @SafeVarargs
    @Nonnull

 *  @author Victor Jonsson, http://victorjonsson.se
 *  @license MIT
 */

Let's first focus on the dependency.

It is just a function that can take all the same parameters that a *path operation function* can take:

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[8:9] *}

That's it.

**2 lines**.

And it has the same shape and structure that all your *path operation functions* have.

You can think of it as a *path operation function* without the "decorator" (without the `@app.get("/some-path")`).

 *  @website http://formvalidator.net/
 *  @author Victor Jonsson, http://victorjonsson.se
 *  @license MIT
 */

// here.
void TF_SetTracingImplementation(const char* name, TF_Status*);

// Creates a new TensorFlow function. A Function is an execution context, and as
// such it can trace operations through TF_ExecuteOperation. After completing
// tracing, a function can be obtained by TF_FinalizeFunction.
TF_ExecutionContext* TF_CreateFunction(const char* fn_name, TF_Status* status);

  Define(1, {add}, {feed1, feed2}, {add, scalar}, {}, true);
  EXPECT_EQ(TF_INVALID_ARGUMENT, TF_GetCode(s_));
  EXPECT_EQ(string("TF_Output scalar:0 is neither in the function body nor "
                   "among function inputs. Encountered while creating "
                   "function 'MyFunc'"),
            string(TF_Message(s_)));
}

void DefineFunction(const char* name, TF_Function** func,

      Collection<F> fromCollection, Function<? super F, T> function) {
    return new TransformedCollection<>(fromCollection, function);
  }

  static class TransformedCollection<F extends @Nullable Object, T extends @Nullable Object>
      extends AbstractCollection<T> {
    final Collection<F> fromCollection;
    final Function<? super F, ? extends T> function;

Maybe you need to start a new version, or you just got tired of running it. 🤷

///

### Lifespan function

The first thing to notice, is that we are defining an async function with `yield`. This is very similar to Dependencies with `yield`.

{* ../../docs_src/events/tutorial003.py hl[14:19] *}

The first part of the function, before the `yield`, will be executed **before** the application starts.

[ -n "$BASH_XTRACEFD" ] && set -x

function _init() {
	## All binaries are static make sure to disable CGO.
	export CGO_ENABLED=0

	## List of architectures and OS to test coss compilation.
	SUPPORTED_OSARCH="linux/ppc64le linux/mips64 linux/amd64 linux/arm64 linux/s390x darwin/arm64 darwin/amd64 freebsd/amd64 windows/amd64 linux/arm linux/386 netbsd/amd64 linux/mips openbsd/amd64"
}

function _build() {
	local osarch=$1

            Doc(
                """
                The function to call after the response is sent.

                It can be a regular `def` function or an `async def` function.
                """
            ),
        ],
        *args: P.args,
        **kwargs: P.kwargs,
    ) -> None:
        """
        Add a function to be called in the background after the response is sent.