```Python
= None
```

or the:

```Python
= Query(default=None)
```

as it will use that `None` as the default value, and that way make the parameter **not required**.

The `Union[str, None]` part allows your editor to provide better support, but it is not what tells FastAPI that this parameter is not required.

///

import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentMap;

/**
 * The reason why a cached entry was removed.
 *
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public enum RemovalCause {
  /**
   * The entry was manually removed by the user. This can result from the user invoking {@link

                                /* Store references to the map and key so that
                                 * SmbFile.resolveDfs can re-insert the dr list with
                                 * the dr that was successful so that subsequent
                                 * attempts to resolve DFS use the last successful
                                 * referral first.
                                 */

	_, ok := val.(string)
	return ok
}

// ContentLengthRange - policy content-length-range field.
type contentLengthRange struct {
	Min   int64
	Max   int64
	Valid bool // If content-length-range was part of policy
}

// PostPolicyForm provides strict static type conversion and validation for Amazon S3's POST policy JSON string.
type PostPolicyForm struct {

environment.title = Production

# Does it enable the Framework internal debug? (true only when emergency)
framework.debug = false

# one day: 86400000, three days: 259200000, five days: 432000000, one week: 604800000, one year: 31556926000
# special script :: absolute mode: $(2014/07/10), relative mode: addDay(3).addMonth(4)

environment.title = Production

# Does it enable the Framework internal debug? (true only when emergency)
framework.debug = false

# one day: 86400000, three days: 259200000, five days: 432000000, one week: 604800000, one year: 31556926000
# special script :: absolute mode: $(2014/07/10), relative mode: addDay(3).addMonth(4)

     * comparator.
     *
     * <p>The sort order is stable, that is, if two entries have values that compare as equivalent,
     * the entry that was inserted first will be first in the built map's iteration order.
     *
     * @throws IllegalStateException if this method was already called
     * @since 19.0
     */
    @CanIgnoreReturnValue
    @Override

   * @param oldCount the expected present count of the element in this multiset
   * @param newCount the desired count of the element in this multiset
   * @return {@code true} if the condition for modification was met. This implies that the multiset
   *     was indeed modified, unless {@code oldCount == newCount}.
   * @throws IllegalArgumentException if {@code oldCount} or {@code newCount} is negative

   * completed.
   */
  public void testDirectExecutorService_awaitTermination_missedSignal() {
    final ExecutorService service = newDirectExecutorService();
    Thread waiter =
        new Thread() {
          @Override
          public void run() {
            try {
              service.awaitTermination(1, DAYS);

     * 
     * The file locator provides details about
     * 
     * @return the fileLocator
     */
    SmbResourceLocator getLocator ();


    /**
     * The context this file was opened with
     * 
     * @return the context associated with this file
     */
    CIFSContext getContext ();


    /**
     * Returns the last component of the target URL. This will