dir ('its') {
                                def ITS_BRANCH = env.CHANGE_BRANCH != null ? env.CHANGE_BRANCH :  env.BRANCH_NAME;
                                try {
                                  echo "Checkout ITs from branch: ${ITS_BRANCH}"
                                  checkout([$class: 'GitSCM',
                                          branches: [[name: ITS_BRANCH]],

                        def WORK_DIR=pwd()
                        def ITS_BRANCH = env.CHANGE_BRANCH != null ? env.CHANGE_BRANCH :  env.BRANCH_NAME;
                        try {
                          echo "Checkout ITs from branch: ${ITS_BRANCH}"
                          checkout([$class: 'GitSCM',
                                  branches: [[name: ITS_BRANCH]],

The history of **FastAPI** is in great part the history of its predecessors.

As said in the section [Alternatives](alternatives.md){.internal-link target=_blank}:

<blockquote markdown="1">

**FastAPI** wouldn't exist if not for the previous work of others.

There have been many tools created before that have helped inspire its creation.

### Top-level application

First, create the main, top-level, **FastAPI** application, and its *path operations*:

```Python hl_lines="3  6-8"
{!../../../docs_src/sub_applications/tutorial001.py!}
```

### Sub-application

Then, create your sub-application, and its *path operations*.

This sub-application is just another standard FastAPI application, but this is the one that will be "mounted":

 * <p>
 * It provides information about the file type (or extension) of the associated artifact,
 * its default classifier, and how the artifact will be used in the build when creating
 * class-paths or module-paths.
 * <p>
 * For example, the type {@code java-source} has a {@code jar} extension and a
 * {@code sources} classifier. The artifact and its dependencies should be added
 * to the build path.
 *
 * @since 4.0.0
 */
@Experimental

  // implementations.

  private Futures() {}

  /**
   * Creates a {@code ListenableFuture} which has its value set immediately upon construction. The
   * getters just return the value. This {@code Future} can't be canceled or timed out and its
   * {@code isDone()} method always returns {@code true}.
   */
  public static <V extends @Nullable Object> ListenableFuture<V> immediateFuture(

import java.util.Queue;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A double-ended priority queue, which provides constant-time access to both its least element and
 * its greatest element, as determined by the queue's specified comparator. If no comparator is
 * given at creation time, the natural order of elements is used. If no maximum size is given at

    }
    copyIntoArray(other, 0);
    return other;
  }

  /** If this collection is backed by an array of its elements in insertion order, returns it. */
  @CheckForNull
  @Nullable
  Object[] internalArray() {
    return null;
  }

  /**
   * If this collection is backed by an array of its elements in insertion order, returns the offset
   * where this collection's elements start.
   */

   *
   * (That would also have ensured that its cause was always an Error, rather than possibly another
   * kind of Throwable that was later passed to initCause. Then we could have declared the override
   * `public final Error getCause()`.)
   */

  /**
   * Creates a new instance with {@code null} as its detail message and no cause.
   *

   *
   * (Perhaps it should also have required that its cause was a RuntimeException. However, that
   * would have required that we throw a different kind of exception for wrapping *checked*
   * exceptions in methods like Futures.getUnchecked and LoadingCache.get.)
   */

  /**
   * Creates a new instance with {@code null} as its detail message and no cause.
   *