*  **OkHttp now uses `@Nullable` to annotate all possibly-null values.** We've
    added a compile-time dependency on the JSR 305 annotations. This is a
    [provided][maven_provided] dependency and does not need to be included in
    your build configuration, `.jar` file, or `.apk`. We use
    `@ParametersAreNonnullByDefault` and all parameters and return types are
    never null unless explicitly annotated `@Nullable`.

  /*
   * Preconditions.checkNotNull is *intended* for performing eager null checks on parameters that a
   * nullness checker can already "prove" are non-null. That means that the first parameter to
   * checkNotNull *should* be annotated to require it to be non-null.
   *
   * However, for a variety of reasons, Google developers have written a ton of code over the past

def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

### Dockerfile

В этой же директории создайте файл `Dockerfile` и заполните его:

```{ .dockerfile .annotate }
# (1)
FROM python:3.9

# (2)
WORKDIR /code

# (3)
COPY ./requirements.txt /code/requirements.txt

# (4)
RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt

# (5)

@J2ktIncompatible
@GwtIncompatible
@SuppressWarnings({
  "GuardedBy", // TODO(b/35466881): Fix or suppress.
  "nullness", // too much trouble for the payoff
})
@NullUnmarked // TODO(cpovirk): Annotate for nullness.
final class MapMakerInternalMap<
        K,
        V,
        E extends MapMakerInternalMap.InternalEntry<K, V, E>,
        S extends MapMakerInternalMap.Segment<K, V, E, S>>