# Background Tasks - `BackgroundTasks`

You can declare a parameter in a *path operation function* or dependency function with the type `BackgroundTasks`, and then you can use it to schedule the execution of background tasks after the response is sent.

You can import it directly from `fastapi`:

```python
from fastapi import BackgroundTasks
```

public class MapComputeIfPresentTester<K, V> extends AbstractMapTester<K, V> {

  @MapFeature.Require(SUPPORTS_PUT)
  public void testComputeIfPresent_supportedAbsent() {
    assertNull(
        "computeIfPresent(notPresent, function) should return null",
        getMap()
            .computeIfPresent(
                k3(),
                (k, v) -> {
                  throw new AssertionFailedError();
                }));
    expectUnchanged();

#!/bin/bash

set -e
# Enable tracing if set.
[ -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 linux/riscv64"
}

chrome.omnibox.onInputEntered.addListener(function(t) {
  var url = urlForInput(t);
  if (url) {
    chrome.tabs.query({ "active": true, "currentWindow": true }, function(tab) {
      if (!tab) return;
      chrome.tabs.update(tab.id, { "url": url, "selected": true });
    });
  }

import com.google.common.base.Function;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Test cases for {@link Tables#transformValues}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public class TablesTransformValuesTest extends AbstractTableTest<Character> {

  private static final Function<@Nullable String, @Nullable Character> FIRST_CHARACTER =

        }
    }

    /**
     * Gets the content of the response using the provided parser function.
     *
     * @param <T> the type of the parsed content.
     * @param parser the function to parse the content.
     * @return the parsed content.
     */
    public <T> T getContent(final Function<CurlResponse, T> parser) {
        return parser.apply(this);
    }

    /**

import org.codelibs.fess.suggest.exception.SuggesterException;
import org.codelibs.fess.suggest.normalizer.Normalizer;
import org.opensearch.common.lucene.search.function.CombineFunction;
import org.opensearch.common.lucene.search.function.FieldValueFactorFunction;
import org.opensearch.common.lucene.search.function.FunctionScoreQuery;
import org.opensearch.core.common.Strings;
import org.opensearch.index.query.BoolQueryBuilder;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.SortedMap;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.stream.Collector;
import org.jspecify.annotations.Nullable;

/**
 * GWT emulated version of {@link com.google.common.collect.ImmutableSortedMap}. It's a thin wrapper

Le code suivant l'instruction `yield` est exécuté après la réponse :

{* ../../docs_src/dependencies/tutorial007_py310.py hl[5:6] *}

/// tip | Astuce

Vous pouvez utiliser des fonctions `async` ou des fonctions classiques.

**FastAPI** fera ce qu'il faut dans chaque cas, comme avec des dépendances normales.

///

## Créer une dépendance avec `yield` et `try` { #a-dependency-with-yield-and-try }

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import com.google.common.base.Function;
import java.util.ListIterator;
import org.jspecify.annotations.Nullable;

/**
 * An iterator that transforms a backing list iterator; for internal use. This avoids the object
 * overhead of constructing a {@link Function} for internal methods.
 *
 * @author Louis Wasserman
 */
@GwtCompatible