import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.Serializable;
import java.lang.reflect.Method;
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Iterator;

                  }
                })
            .named("ImmutableSortedMultiset.asList")
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.SERIALIZABLE,
                CollectionFeature.ALLOWS_NULL_QUERIES)
            .createTestSuite());

    suite.addTest(
        ListTestSuiteBuilder.using(
                new TestStringListGenerator() {

                CollectionFeature.ALLOWS_NULL_QUERIES,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.NON_STANDARD_TOSTRING,
                CollectionFeature.SERIALIZABLE)
            .createTestSuite());

    suite.addTest(
        NavigableSetTestSuiteBuilder.using(new ImmutableRangeSetBigIntegerAsSetGenerator())

import com.google.j2objc.annotations.RetainedWith;
import com.google.j2objc.annotations.WeakOuter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.function.BiFunction;
import org.jspecify.annotations.Nullable;

                MapFeature.GENERAL_PURPOSE,
                MapFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION,
                CollectionFeature.SUPPORTS_ITERATOR_REMOVE,
                CollectionFeature.SERIALIZABLE,
                CollectionSize.ANY)
            .createTestSuite());
    suite.addTestSuite(ArrayListMultimapTest.class);
    return suite;
  }

  protected ListMultimap<String, Integer> create() {

import com.google.common.util.concurrent.ListeningExecutorService;
import com.google.common.util.concurrent.SettableFuture;
import com.google.common.util.concurrent.UncheckedExecutionException;
import java.io.Serializable;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;

import com.google.common.util.concurrent.ListeningExecutorService;
import com.google.common.util.concurrent.SettableFuture;
import com.google.common.util.concurrent.UncheckedExecutionException;
import java.io.Serializable;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;

import org.gradle.api.GradleException
import org.gradle.api.file.DirectoryProperty
import org.gradle.api.file.FileSystemOperations
import org.gradle.api.internal.tasks.testing.results.serializable.SerializableTestResultStore
import org.gradle.api.provider.MapProperty
import org.gradle.api.services.BuildService
import org.gradle.api.services.BuildServiceParameters
import org.gradle.api.tasks.testing.TestResult

defecto, FastAPI inspeccionará cada elemento dentro y se asegurará de que sea serializable como JSON, usando el mismo [Codificador Compatible con JSON](../tutorial/encoder.md){.internal-link target=_blank} explicado en el tutorial. Esto es lo que te permite devolver **objetos arbitrarios**, por ejemplo, modelos de bases de datos.

Pero si estás seguro de que el contenido que estás devolviendo es **serializable con JSON**, puedes pasarlo directamente a la clase de response y evitar la sobrecarga...

 * A {@code BiMap} backed by an {@code EnumMap} instance for keys-to-values, and a {@code HashMap}
 * instance for values-to-keys. Null keys are not permitted, but null values are. An {@code
 * EnumHashBiMap} and its inverse are both serializable.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#bimap">{@code BiMap}</a>.
 *
 * @author Mike Bostock
 * @since 2.0
 */
@GwtCompatible