### 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":

        return iterator.hasNext();
      }

      @Override
      @ParametricNullness
      public T next() {
        return iterator.next();
      }
    };
  }

  /**
   * Simply returns its argument.
   *
   * @deprecated no need to use this
   * @since 10.0
   */
  @Deprecated
  public static <T extends @Nullable Object> UnmodifiableIterator<T> unmodifiableIterator(

package org.apache.maven.api.services;

/**
 * Describes a problem that was encountered during model building. A problem can either be an exception that was thrown
 * or a simple string message. In addition, a problem carries a hint about its source, e.g. the POM file that exhibits
 * the problem.
 *
 */
public interface ModelProblem extends BuilderProblem {

    /**
     * Version
     */
    enum Version {

 * <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

    }
    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.
   */

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

  /** If this collection is backed by an array of its elements in insertion order, returns it. */
  @CheckForNull
  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.
   */
  int internalArrayStart() {

  // 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(

# this PR, this automations will have its `if` checked to run.  In a way, the `on` conditions
# function as an implicit first `if` for every automation in the file.

# You can define multiple automations in a .cm file, but each automation name should be unique
# within the file.  We keep each automation (or very closely related group of automations) in
# its own file.

on:
  - pr_created
  - commit

# this PR, this automations will have its `if` checked to run.  In a way, the `on` conditions
# function as an implicit first `if` for every automation in the file.

# You can define multiple automations in a .cm file, but each automation name should be unique
# within the file.  We keep each automation (or very closely related group of automations) in
# its own file.

on:
  - pr_created
  - commit

   * other methods are supported by the multimap and its views. When adding a key that doesn't
   * satisfy the predicate, the multimap's {@code put()}, {@code putAll()}, and {@code
   * replaceValues()} methods throw an {@link IllegalArgumentException}.
   *
   * <p>When methods such as {@code removeAll()} and {@code clear()} are called on the filtered