import com.google.errorprone.annotations.CanIgnoreReturnValue;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests unconditional {@code setCount()} operations on a multiset. Can't
 * be invoked directly; please see {@link MultisetTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

import com.google.common.collect.testing.features.CollectionSize;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests {@code isEmpty()} operations on a collection. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible

}
```

#### Unwrapping a `dict`

If we take a `dict` like `user_dict` and pass it to a function (or class) with `**user_dict`, Python will "unwrap" it. It will pass the keys and values of the `user_dict` directly as key-value arguments.

So, continuing with the `user_dict` from above, writing:

```Python
UserInDB(**user_dict)
```

would result in something equivalent to:

```Python
UserInDB(

  -java-home <path>  Alternate JAVA_HOME

  # jvm options and output control
  -Dkey=val          Pass -Dkey=val directly to the java runtime
  -J-X               Pass option -X directly to the java runtime
                     (-J is stripped)

  # environment variables (read from context)
  JAVA_OPTS          Environment variable, if unset uses ""

public interface SourceSinkFactory<S, T> {

  /**
   * Returns the data to expect the source or sink to contain given the data that was used to create
   * the source or written to the sink. Typically, this will just return the input directly, but in
   * some cases it may alter the input. For example, if the factory returns a sliced view of a
   * source created with some given bytes, this method would return a subsequence of the given
   * (byte[]) data.
   */

///

## Add custom headers

There are some situations in where it's useful to be able to add custom headers to the HTTP error. For example, for some types of security.

You probably won't need to use it directly in your code.

But in case you needed it for an advanced scenario, you can add custom headers:

```Python hl_lines="14"
{!../../docs_src/handling_errors/tutorial002.py!}
```

## Install custom exception handlers

///

### Namenskollisionen vermeiden

Wir importieren das Submodul `items` direkt, anstatt nur seine Variable `router` zu importieren.

Das liegt daran, dass wir im Submodul `users` auch eine weitere Variable namens `router` haben.

Wenn wir eine nach der anderen importiert hätten, etwa:

import com.google.common.collect.Multisets;
import com.google.common.collect.testing.features.CollectionSize;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests multiset-specific read operations. Can't be invoked directly;
 * please see {@link com.google.common.collect.testing.SetTestSuiteBuilder}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

import com.google.common.collect.Multisets;
import com.google.common.collect.testing.features.CollectionSize;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests multiset-specific read operations. Can't be invoked directly;
 * please see {@link com.google.common.collect.testing.SetTestSuiteBuilder}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import org.junit.Ignore;

/**
 * A generic JUnit test which tests conditional {@code setCount()} operations on a multiset. Can't
 * be invoked directly; please see {@link MultisetTestSuiteBuilder}.
 *
 * @author Chris Povirk
 */
@GwtCompatible
@Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.