{!> ../../docs_src/dependency_testing/tutorial001.py!}
```

////

/// tip | "Tipp"

Sie können eine Überschreibung für eine Abhängigkeit festlegen, die an einer beliebigen Stelle in Ihrer **FastAPI**-Anwendung verwendet wird.

Die ursprüngliche Abhängigkeit könnte in einer *Pfadoperation-Funktion*, einem *Pfadoperation-Dekorator* (wenn Sie den Rückgabewert nicht verwenden), einem `.include_router()`-Aufruf, usw. verwendet werden.

  }

  /**
   * Wrapper for {@link Map#get(Object)} that forces the caller to pass in a key of the same type as
   * the map. Besides being slightly shorter than code that uses {@link #getMap()}, it also ensures
   * that callers don't pass an {@link Entry} by mistake.
   */
  protected V get(K key) {
    return getMap().get(key);
  }

 * on [ExchangeCodec], which handles the actual I/O.
 */
class Exchange(
  internal val call: RealCall,
  internal val eventListener: EventListener,
  internal val finder: ExchangeFinder,
  private val codec: ExchangeCodec,
) {
  /** True if the request body need not complete before the response body starts. */
  internal var isDuplex: Boolean = false
    private set

    this.lastInKeyInsertionOrder = null;
    this.size = 0;
    this.mask = tableSize - 1;
    this.modCount = 0;
  }

  /**
   * Finds and removes {@code entry} from the bucket linked lists in both the key-to-value direction
   * and the value-to-key direction.
   */
  private void delete(BiEntry<K, V> entry) {
    int keyBucket = entry.keyHash & mask;
    BiEntry<K, V> prevBucketEntry = null;

  }

  /**
   * Wrapper for {@link Map#get(Object)} that forces the caller to pass in a key of the same type as
   * the map. Besides being slightly shorter than code that uses {@link #getMap()}, it also ensures
   * that callers don't pass an {@link Entry} by mistake.
   */
  protected V get(K key) {
    return getMap().get(key);
  }

    setSucceeds(oldPredecessor, oldSuccessor); // remove from insertion order linked list

    deleteFromTableKToV(entry, Hashing.smearedHash(keys[entry]));
    keys[entry] = newKey;
    insertIntoTableKToV(entry, Hashing.smearedHash(newKey));

    // insert into insertion order linked list, usually at the end
    setSucceeds(newPredecessor, entry);
    setSucceeds(entry, newSuccessor);
  }

## Mounten einer **FastAPI**-Anwendung

„Mounten“ („Einhängen“) bedeutet das Hinzufügen einer völlig „unabhängigen“ Anwendung an einem bestimmten Pfad, die sich dann um die Handhabung aller unter diesem Pfad liegenden _Pfadoperationen_ kümmert, welche in dieser Unteranwendung deklariert sind.

import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import com.google.caliper.api.SkipThisScenarioException;
import java.util.List;

/**
 * Quick and dirty benchmark of {@link Throwables#lazyStackTrace(Throwable)}. We benchmark a "caller
 * finder" implementation that might be used in a logging framework.
 */
public class LazyStackTraceBenchmark {
  @Param({"20", "200", "2000"})
  int stackDepth;

  @Param({"-1", "3", "15"})

import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import com.google.caliper.api.SkipThisScenarioException;
import java.util.List;

/**
 * Quick and dirty benchmark of {@link Throwables#lazyStackTrace(Throwable)}. We benchmark a "caller
 * finder" implementation that might be used in a logging framework.
 */
public class LazyStackTraceBenchmark {
  @Param({"20", "200", "2000"})
  int stackDepth;

  @Param({"-1", "3", "15"})

    /*
     * TODO(cpovirk): Clear interrupt status here? We currently don't, which means that an interrupt
     * before, during, or after runInterruptibly() (unless it produced an InterruptedException
     * caught above) can linger and affect listeners.
     */
  }

  /**
   * Called before runInterruptibly - if true, runInterruptibly and afterRanInterruptibly will not
   * be called.
   */
  abstract boolean isDone();