That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.

The way to describe this in OpenAPI, is to mark that field as **required**, because it will always be there.

Because of that, the JSON Schema for a model can be different depending on if it's used for **input or output**:

### Container Images

All container images are available as manifest lists and support the described
architectures. It is also possible to pull a specific architecture directly by
adding the "-$ARCH" suffix  to the container image name.

name | architectures
---- | -------------

  // items is a list of schema objects.
  repeated RuntimeClass items = 2;
}

// RuntimeClassSpec is a specification of a RuntimeClass. It contains parameters
// that are required to describe the RuntimeClass to the Container Runtime
// Interface (CRI) implementation, as well as any other components that need to
// understand how the pod will be run. The RuntimeClassSpec is immutable.
message RuntimeClassSpec {

   * value that are {@linkplain Range#isConnected connected} to this range.
   *
   * <p>The behavior of {@link #get(Comparable) get(k)} after calling this method is identical to
   * the behavior described in {@link #put(Range, Object) put(range, value)}, however the ranges
   * returned from {@link #asMapOfRanges} will be different if there were existing entries which
   * connect to the given range and value.
   *

    listeners.add(new PerListenerQueue<>(listener, executor));
  }

  /**
   * Enqueues an event to be run on currently known listeners.
   *
   * <p>The {@code toString} method of the Event itself will be used to describe the event in the
   * case of an error.
   *
   * @param event the callback to execute on {@link #dispatch}
   */
  public void enqueue(Event<L> event) {
    enqueueHelper(event, event);
  }

  /**

// There should be no retries in this function,
// and should have a timeout of something like 2 seconds.
// The returned net.Conn should also have quick disconnect on errors.
// The net.Conn must support all features as described by the net.Conn interface.
type ConnDialer func(ctx context.Context, address string) (net.Conn, error)

// ConnectWSWithRoutePath is like ConnectWS but with a custom grid route path.

  This way you can make sure you're not wasting your time on something that isn't
  considered to be in Apache Maven's scope.
+ Submit a ticket for your issue, assuming one does not already exist.
  + Clearly describe the issue, including steps to reproduce when it is a bug.
  + Make sure you fill in the earliest version that you know has the issue.
+ Fork the repository on GitHub.

Making and Submitting Changes
--------------

TensorFlow via the command `import tensorflow as tf`.

The primary function of this module is to import all of the public TensorFlow
interfaces into a single place. The interfaces themselves are located in
sub-modules, as described below.

Note that the file `__init__.py` in the TensorFlow source code tree is actually
only a placeholder to enable test cases to run. The TensorFlow build replaces

  /**
   * Returns a {@link Collection} of all the permutations of the specified {@link Iterable}.
   *
   * <p><i>Notes:</i> This is an implementation of the algorithm for Lexicographical Permutations
   * Generation, described in Knuth's "The Art of Computer Programming", Volume 4, Chapter 7,
   * Section 7.2.1.2. The iteration order follows the lexicographical order. This means that the

// metrics group.
func (mg *MetricsGroup) IsBucketMetricsGroup() bool {
	return mg.bucketLoader != nil
}

// Describe - implements prometheus.Collector interface.
func (mg *MetricsGroup) Describe(ch chan<- *prometheus.Desc) {
	for _, desc := range mg.Descriptors {
		ch <- desc.toPromDesc(mg.CollectorPath.metricPrefix(), mg.ExtraLabels)
	}
}