* is the only one in use, but if we encounter nested concatenations, we start a deque of
     * meta-iterators rather than letting the nesting get arbitrarily deep.  This keeps each
     * operation O(1).
     */

    private @Nullable Iterator<? extends Iterator<? extends T>> topMetaIterator;

    // Only becomes nonnull if we encounter nested concatenations.

    assertThrows(IllegalArgumentException.class, () -> Maps.subMap(map, Range.closed(4, 8)));

    // These results are all incorrect, but there's no way (short of iterating over the result)
    // to verify that with an arbitrary ordering or comparator.
    assertEquals(ImmutableSortedMap.of(2, 0, 4, 0), Maps.subMap(map, Range.atLeast(4)));
    assertEquals(ImmutableSortedMap.of(8, 0, 10, 0), Maps.subMap(map, Range.atMost(8)));
    assertEquals(

    * New documentation about returning arbitrary `dict`s in responses: [Response with arbitrary `dict`](https://fastapi.tiangolo.com/tutorial/extra-models/#response-with-arbitrary-dict).
    * **Technical Details**:
        * When declaring a `response_model` it is used directly to generate the response content, from whatever was returned from the *path operation function*.

## Kubefed

* Deprecate the `--secret-name` flag from `kubefed join`, instead generating the secret name arbitrarily. ([#42513](https://github.com/kubernetes/kubernetes/pull/42513), [@perotinus](https://github.com/perotinus))


### **Kubernetes API**
#### User Provided Extensions

- Kube-apiserver: Resolved an issue causing unnecessary warning log messages about...

* Return "410 Gone" errors via watch stream when using watch cache ([#25369](https://github.com/kubernetes/kubernetes/pull/25369), [@liggitt](https://github.com/liggitt))
* GKE provider: Add cluster-ipv4-cidr and arbitrary flags ([#25437](https://github.com/kubernetes/kubernetes/pull/25437), [@zmerlynn](https://github.com/zmerlynn))

- Kubelet can now parse PEM file containing both TLS certificate and key in arbitrary order. Previously key was always required to be first. ([#69536](https://github.com/kubernetes/kubernetes/pull/69536), [@awly](https://github.com/awly))

- Kubelet: Closed a loophole that allowed static Pods to reference arbitrary ResourceClaims. Even though these Pods failed to run due to a sanity check, such references are now explicitly disallowed. ([#131844](https://github.com/kubernetes/kubernetes/pull/131844), [@pohly](https://github.com/pohly)) [SIG Apps, Auth and Node]...

affinity/anti-affinity allow you to specify rules for restricting which node(s) a pod can schedule onto, based on the labels on the node. Pod affinity/anti-affinity allow you to specify rules for spreading and packing pods relative to one another, across arbitrary topologies (node, zone, etc.) These affinity rules are now be specified in a new-in-1.6 `affinity` field of the PodSpec. Kubernetes 1.6 continues to support the alpha `scheduler.alpha.kubernetes.io/affinity` annotation on the Pod if you explicitly...

- Kubelet: close a loophole where static pods could reference arbitrary ResourceClaims. The pods created by the kubelet then don't run due to a sanity check, but such references shouldn't be allowed regardless. ([#131875](https://github.com/kubernetes/kubernetes/pull/131875), [@pohly](https://github.com/pohly)) [SIG...