if (offset + SIGNATURE_OFFSET + SIGNATURE_LENGTH > data.length) {
            throw new IllegalArgumentException("Signature field exceeds data buffer size");
        }

        // Use fine-grained locking for better concurrency
        this.signingLock.lock();
        try {
            if (this.closed) {
                throw new IllegalStateException("SigningDigest is closed");
            }

 *
 * <p>The {@link #count} and {@link #size} implementations all iterate across the set returned by
 * {@link Multiset#entrySet()}, as do many methods acting on the set returned by {@link
 * #elementSet()}. Override those methods for better performance.
 *
 * @author Kevin Bourrillion
 * @author Louis Wasserman
 */
@GwtCompatible
abstract class AbstractMultiset<E extends @Nullable Object> extends AbstractCollection<E>
    implements Multiset<E> {

    assertEquals(c, navigableSet.higher(b));
    assertEquals(null, navigableSet.higher(c));
  }

  /*
   * TODO(cpovirk): make "too small" and "too large" elements available for better navigation
   * testing. At that point, we may be able to eliminate the "hole" tests, which would mean that
   * ContiguousSet's tests would no longer need to suppress them.
   */
  @CollectionSize.Require(SEVERAL)

   * interned, thus preventing these instances from being garbage-collected. If this retention is
   * acceptable, this implementation may perform better than {@link #newWeakInterner}.
   */
  public static <E> Interner<E> newStrongInterner() {
    return newBuilder().strong().build();
  }

  /**

    assertEquals(c, navigableSet.higher(b));
    assertEquals(null, navigableSet.higher(c));
  }

  /*
   * TODO(cpovirk): make "too small" and "too large" elements available for better navigation
   * testing. At that point, we may be able to eliminate the "hole" tests, which would mean that
   * ContiguousSet's tests would no longer need to suppress them.
   */
  @CollectionSize.Require(SEVERAL)

And we know that editors can't provide a lot of support (like completion) for `dict`s, because they can't know their keys and value types.

We can do better...

## What makes a dependency { #what-makes-a-dependency }

Up to now you have seen dependencies declared as functions.

    assertThat(Resources.toByteArray(resource)).isEqualTo(I18N.getBytes(UTF_8));
  }

  public void testReadLines() throws IOException {
    // TODO(chrisn): Check in a better resource
    URL resource = getClass().getResource("testdata/i18n.txt");
    assertEquals(ImmutableList.of(I18N), Resources.readLines(resource, UTF_8));
  }

   2. Add Javadoc to existing code if you can.
   3. Document the "why", not the "how", unless that's important to the
      "why".
   4. Don't document anything trivial or obvious (e.g. getters and
      setters). In other words, the Javadoc should add some value.

#### The long version

   1. If you add a new Java package, please also add package-level

And these models are all sharing a lot of the data and duplicating attribute names and types.

We could do better.

We can declare a `UserBase` model that serves as a base for our other models. And then we can make subclasses of that model that inherit its attributes (type declarations, validation, etc).

/// note

FastAPI will know that the value of `q` is not required because of the default value `= None`.

Having `str | None` will allow your editor to give you better support and detect errors.

///

## Additional validation { #additional-validation }

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.