```Python hl_lines="1  4"
{!../../docs_src/python_types/tutorial009.py!}
```

Using `Optional[str]` instead of just `str` will let the editor help you detect errors where you could be assuming that a value is always a `str`, when it could actually be `None` too.

`Optional[Something]` is actually a shortcut for `Union[Something, None]`, they are equivalent.

 }\n\n  let arrowElement = options.element;\n\n  // if arrowElement is a string, suppose it's a CSS selector\n  if (typeof arrowElement === 'string') {\n    arrowElement = data.instance.popper.querySelector(arrowElement);\n\n    // if arrowElement is not found, don't run the modifier\n    if (!arrowElement) {\n      return data;\n    }\n  } else {\n    // if the arrowElement isn't a query selector we must check that the\n    // provided DOM node is child of its popper node\n    if (!data.instanc...

   * 'affect' a bit(j) in the output if two inputs, identical but for bit(i), will differ at output
   * bit(j) about half the time
   *
   * <p>Funneling is pretty simple to detect. The key idea is to find example keys which
   * unequivocally demonstrate that funneling cannot be occurring. This is done bit-by-bit. For each

 * governing permissions and limitations under the License.
 */
package org.codelibs.core.lang;

import static org.codelibs.core.collection.CollectionsUtil.newArrayList;

import java.lang.reflect.Method;
import java.util.List;
import java.util.StringTokenizer;

/**
 * {@link String}用のユーティリティクラスです。
 *
 * @author higa
 * @author shinsuke
 */
public abstract class StringUtil {

    /**

- find accounts whose group memberships have changed; access policies available to a credential are updated to reflect the change, i.e. they will lose any privileges associated with a group they are removed from, and gain any privileges associated with a group they are added to.

* An "Init Container" in Kubernetes that runs before your app container
* A bash script that runs the previous steps and then starts your application
    * You would still need a way to start/restart *that* bash script, detect errors, etc.

/// tip

I'll give you more concrete examples for doing this with containers in a future chapter: [FastAPI in Containers - Docker](docker.md){.internal-link target=_blank}.

///

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.reflect;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.StandardSystemProperty.JAVA_CLASS_PATH;

       *
       * - ServiceDelegate.runningTask contains an instance of ReschedulableCallable (at least in
       *   the case that the service is using CustomScheduler). (It needs it so that it can cancel
       *   the task and detect whether it has been cancelled.)
       *
       * - ReschedulableCallable has a reference back to its enclosing CustomScheduler. (It needs it
       *   so that it can call getNextSchedule).
       *

    * If you are upgrading your Cluster Federation components from v1.3.x, please run this command to migrate the federation-apiserver-secret to federation-apiserver-kubeconfig serect;
    ```$ kubectl --namespace=federation get secret federation-apiserver-secret -o json | sed 's/federation-apiserver-secret/federation-apiserver-kubeconfig/g' | kubectl create -f -```

  @Test fun ipv6AddressMalformed() {
    val cookie = parse("http://[::1]/".toHttpUrl(), "a=b; domain=::2::2")
    assertThat(cookie!!.domain).isEqualTo("::1")
  }

  /**
   * These public suffixes were selected by inspecting the publicsuffix.org list. It's possible they
   * may change in the future. If this test begins to fail, please double check they are still
   * present in the public suffix list.
   */