By ✨ [**sponsoring FastAPI**](../help-fastapi.md#sponsor-the-author){.internal-link target=_blank} ✨, these companies help ensure the framework and its **ecosystem** remain healthy and **sustainable**.

@GwtCompatible
final class NullnessCasts {
  /**
   * Accepts a {@code @Nullable T} and returns a plain {@code T}, without performing any check that
   * that conversion is safe.
   *
   * <p>This method is intended to help with usages of type parameters that have {@linkplain
   * ParametricNullness parametric nullness}. If a type parameter instead ranges over only non-null

@GwtCompatible
final class NullnessCasts {
  /**
   * Accepts a {@code @Nullable T} and returns a plain {@code T}, without performing any check that
   * that conversion is safe.
   *
   * <p>This method is intended to help with usages of type parameters that have {@linkplain
   * ParametricNullness parametric nullness}. If a type parameter instead ranges over only non-null

{* ../../docs_src/dependencies/tutorial005_an_py310.py hl[8:9] *}

It declares an optional query parameter `q` as a `str`, and then it just returns it.

This is quite simple (not very useful), but will help us focus on how the sub-dependencies work.

## Second dependency, "dependable" and "dependant" { #second-dependency-dependable-and-dependant }

    public UnmodifiableIterator<Entry<K, V>> iterator() {
      return entries.iterator();
    }

    @Override
    ImmutableList<Entry<K, V>> createAsList() {
      return entries;
    }

    // redeclare to help optimizers with b/310253115
    @SuppressWarnings("RedundantOverride")
    @Override
    @J2ktIncompatible
    @GwtIncompatible
        Object writeReplace() {
      return super.writeReplace();
    }
  }

      }

      @Override
      boolean isPartialView() {
        return true;
      }

      @Override
      public int size() {
        return entryList.size();
      }

      // redeclare to help optimizers with b/310253115
      @SuppressWarnings("RedundantOverride")
      @Override
      @J2ktIncompatible
      @GwtIncompatible
            Object writeReplace() {
        return super.writeReplace();
      }

    return entries.get(index);
  }

  @Override
  boolean isPartialView() {
    return false;
  }

  @Override
  public int size() {
    return Ints.saturatedCast(size);
  }

  // redeclare to help optimizers with b/310253115
  @SuppressWarnings("RedundantOverride")
  @Override
  @J2ktIncompatible
  @GwtIncompatible
    Object writeReplace() {
    return super.writeReplace();
  }

											<la:message key="labels.login" />
										</la:link></li>
								</c:when>
							</c:choose>
							<li class="nav-item"><la:link href="/help" styleClass="nav-link help-link">
									<i class="fa fa-fw fa-question-circle" aria-hidden="true"></i>
									<la:message key="labels.index_help" />
								</la:link></li>
						</ul>
					</div>
				</div>
			</nav>

Но, тем не менее, грядёт добавление ещё многих улучшений и возможностей.

У **FastAPI** великое будущее.

Some editors check for unused function parameters, and show them as errors.

Using these `dependencies` in the *path operation decorator* you can make sure they are executed while avoiding editor/tooling errors.

It might also help avoid confusion for new developers that see an unused parameter in your code and could think it's unnecessary.

///

/// info

In this example we use invented custom headers `X-Key` and `X-Token`.