**FastAPI** is all based on these type hints, they give it many advantages and benefits.

But even if you never use **FastAPI**, you would benefit from learning a bit about them.

/// note

If you are a Python expert, and you already know everything about type hints, skip to the next chapter.

///

## Motivation

   */
  open fun proxySelectStart(
    call: Call,
    url: HttpUrl,
  ) {
  }

  /**
   * Invoked after proxy selection.
   *
   * Note that the list of proxies is never null, but it may be a list containing
   * only [Proxy.NO_PROXY]. This comes up in several situations:
   *
   * * If neither a proxy nor proxy selector is configured.

   *
   * <p>The returned table will be serializable if the specified table is serializable.
   *
   * <p>Consider using an {@link ImmutableTable}, which is guaranteed never to change.
   *
   * @since 11.0
   */
  public static <R extends @Nullable Object, C extends @Nullable Object, V extends @Nullable Object>

          action.accept(node);
        }
      }
    }
    return new EntriesImpl();
  }

  @Override
  Iterator<Entry<K, V>> entryIterator() {
    throw new AssertionError("should never be called");
  }

  @Override
  Map<K, Collection<V>> createAsMap() {
    return new Multimaps.AsMap<>(this);
  }

  /**

   * primary input fails with the given {@code exceptionType}, from the result provided by the
   * {@code fallback}. {@link Function#apply} is not invoked until the primary input has failed, so
   * if the primary input succeeds, it is never invoked. If, during the invocation of {@code
   * fallback}, an exception is thrown, this exception is used as the result of the output {@code
   * Future}.
   *
   * <p>Usage example:
   *
   * <pre>{@code

    /** Gets the weak value reference held by entry. */
    WeakValueReference<K, V, E> getValueReference();
  }

  @SuppressWarnings("unchecked") // impl never uses a parameter or returns any non-null value
  static <K, V, E extends InternalEntry<K, V, E>>
      WeakValueReference<K, V, E> unsetWeakValueReference() {
    return (WeakValueReference<K, V, E>) UNSET_WEAK_VALUE_REFERENCE;

    return method.getName().startsWith("enter") || method.getName().startsWith("tryEnter");
  }

  /** Identifies just tryEnterXxx methods (a subset of {@link #isAnyEnter}), which never block. */
  private static boolean isTryEnter(Method method) {
    return method.getName().startsWith("tryEnter");
  }

  /**

		// - this change attempts to avoid stale information if the underlying
		// transport is already down.
		return "", errDiskNotFound
	}

	// This call should never be over the network, this is always
	// a cached value - caller should make sure to use this
	// function on a fresh disk or make sure to look at the error
	// from a different networked call to validate the GetDiskID()

	switch ef.Type {
	case BatchJobExpireObject:
		if obj.DeleteMarker {
			return false
		}
	case BatchJobExpireDeleted:
		if !obj.DeleteMarker {
			return false
		}
	default:
		// we should never come here, Validate should have caught this.
		batchLogOnceIf(context.Background(), fmt.Errorf("invalid filter type: %s", ef.Type), ef.Type)
		return false
	}

	if len(ef.Name) > 0 && !wildcard.Match(ef.Name, obj.Name) {

  // `type` indicates whether this priority level is subject to
  // limitation on request execution.  A value of `"Exempt"` means
  // that requests of this priority level are not subject to a limit
  // (and thus are never queued) and do not detract from the
  // capacity made available to other priority levels.  A value of
  // `"Limited"` means that (a) requests of this priority level