/**
   * Adds {@code node} if it is not already present.
   *
   * <p><b>Nodes must be unique</b>, just as {@code Map} keys must be. They must also be non-null.
   *
   * @return {@code true} if the graph was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean addNode(N node);

  /**
   * Adds an edge connecting {@code nodeU} to {@code nodeV} if one is not already present, and sets

      "Cannot call source()/target() on a EndpointPair from an undirected graph. Consider calling "
          + "adjacentNode(node) if you already have a node, or nodeU()/nodeV() if you don't.";
  static final String EDGE_ALREADY_EXISTS = "Edge %s already exists in the graph.";
  static final String ENDPOINTS_MISMATCH =
      "Mismatch: endpoints' ordering is not compatible with directionality of the graph";

   * @throws IllegalStateException if an initial capacity was already set
   */
  @CanIgnoreReturnValue
  public MapMaker initialCapacity(int initialCapacity) {
    checkState(
        this.initialCapacity == UNSET_INT,
        "initial capacity was already set to %s",
        this.initialCapacity);
    checkArgument(initialCapacity >= 0);

   * be transmitted before the close message is sent but subsequent calls to [send] will return
   * false and their messages will not be enqueued.
   *
   * This returns true if a graceful shutdown was initiated by this call. It returns false if
   * a graceful shutdown was already underway or if the web socket is already closed or canceled.
   *

    /** The object name is invalid */
    int NT_STATUS_OBJECT_NAME_INVALID = 0xC0000033;
    /** The object was not found */
    int NT_STATUS_OBJECT_NAME_NOT_FOUND = 0xC0000034;
    /** The object name already exists */
    int NT_STATUS_OBJECT_NAME_COLLISION = 0xC0000035;
    /** The port is disconnected */
    int NT_STATUS_PORT_DISCONNECTED = 0xC0000037;
    /** The object path is invalid */

    // If the task is already scheduled, take the earlier of the two times.
    val existingIndex = futureTasks.indexOf(task)
    if (existingIndex != -1) {
      if (task.nextExecuteNanoTime <= executeNanoTime) {
        taskRunner.logger.taskLog(task, this) { "already scheduled" }
        return false
      }
      futureTasks.removeAt(existingIndex) // Already scheduled later: reschedule below!
    }

      this.mutableValueGraph =
          graphBuilder.copy().incidentEdgeOrder(ElementOrder.<N>stable()).build();
    }

    /**
     * Adds {@code node} if it is not already present.
     *
     * <p><b>Nodes must be unique</b>, just as {@code Map} keys must be. They must also be non-null.
     *
     * @return this {@code Builder} object
     */
    @CanIgnoreReturnValue

# ==============================================================================
if [[ "$TFCI_DOCKER_PULL_ENABLE" == 1 ]]; then
  # Simple retry logic for docker-pull errors. Sleeps if a pull fails.
  # Pulling an already-pulled container image will finish instantly, so
  # repeating the command costs nothing.
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 15
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 30

But we want to be able to parameterize that fixed content.

## A "callable" instance { #a-callable-instance }

In Python there's a way to make an instance of a class a "callable".

Not the class itself (which is already a callable), but an instance of that class.

To do that, we declare a method `__call__`:

{* ../../docs_src/dependencies/tutorial011_an_py39.py hl[12] *}

    }
  }

  /**
   * Returns an immediately-executable task for the calling thread to execute, sleeping as necessary
   * until one is ready. If there are no ready queues, or if other threads have everything under
   * control this will return null. If there is more than a single task ready to execute immediately
   * this will start another thread to handle that work.
   */
  fun awaitTaskToRun(): Task? {
    assertLockHeld()