FastAPI version 0.119.0 introduced partial support for Pydantic v1 from inside of Pydantic v2 (as `pydantic.v1`), to facilitate the migration to v2.

FastAPI 0.126.0 dropped support for Pydantic v1, while still supporting `pydantic.v1` for a little while.

/// warning

The Pydantic team stopped support for Pydantic v1 for the latest versions of Python, starting with **Python 3.14**.

Let's say the file dedicated to handling just users is the submodule at `/app/routers/users.py`.

You want to have the *path operations* related to your users separated from the rest of the code, to keep it organized.

But it's still part of the same **FastAPI** application/web API (it's part of the same "Python Package").

You can create the *path operations* for that module using `APIRouter`.

### Import `APIRouter` { #import-apirouter }

    /**
     * Returns the tree handle associated with this file handle
     *
     * @return the tree
     */
    SmbTreeHandle getTree();

    /**
     * Checks if this file handle is still valid
     *
     * @return whether the file descriptor is valid
     */
    boolean isValid();

    /**
     * Closes this file handle and optionally sets the last write time
     *

     */
    BEFORE("before:"),
    /**
     * Execution is the execution of the phase proper. Failure of any {@code #AT} dynamic phase execution will fail
     * the phase. Any {@link #AFTER} phases will still be executed.
     */
    AT(""),
    /**
     * Guaranteed execution dynamic phases on completion of the static phase. All {@code #AFTER} dynamic phases will

  public <S extends @Nullable T> Ordering<S> reverse() {
    // ordering.reverse() might be optimized, so let it do its thing
    return ordering.<T>reverse().<@NonNull S>nullsLast();
  }

  @SuppressWarnings("unchecked") // still need the right way to explain this
  @Override
  public <S extends @Nullable T> Ordering<@Nullable S> nullsFirst() {
    return (Ordering<@Nullable S>) this;
  }

  @Override

 * successful execution of the Mojo.
 *
 * <p>
 * Annotations:
 * </p>
 * <ul>
 * <li>{@link Experimental}: Indicates that this interface or its implementation
 * may still be evolving and could change in future versions.</li>
 * <li>{@link FunctionalInterface}: Denotes that this is a functional interface,
 * allowing implementations as lambda expressions or method references.</li>

    @Deprecated
    private Map<String, LifecyclePhase> phases;

    /**
     * Default ctor for plexus compatibility: lifecycles are most commonly defined in Plexus XML, that does field
     * injection. Still, for Plexus to be able to instantiate this class, default ctor is needed.
     *
     * @deprecated Should not be used in Java code.
     */
    @Deprecated
    public DefaultLifecycleMapping() {}

    /**

     * are used to distinguish the various services on a host. <a
     * href="../../../nbtcodes.html">Here</a> is
     * a fairly complete list of NetBIOS hex codes. Scope is not used but is
     * still functional in other NetBIOS products and so for completeness it has been
     * implemented. A <code>scope</code> of <code>null</code> or <code>""</code>
     * signifies no scope.
     *

 * rarely use it directly, in part because it does not provide direct access to the {@code Future}
 * result. (If you want such access, you may prefer {@link Futures#addCallback
 * Futures.addCallback}.) Still, direct {@code addListener} calls are occasionally useful:
 *
 * {@snippet :
 * final String name = ...;
 * inFlight.add(name);
 * ListenableFuture<Result> future = service.query(name);

  with default values defined in {{{../../compat/maven-resolver-provider/apidocs/org/apache/maven/repository/internal/type/DefaultTypeProvider.html}DefaultTypeProvider}}.

  For compatibility, legacy Maven 3 artifact handlers are still provided:

*--------------------+---------------+------------+------------+-----------+---------------------+-----------------------+