"path",
        "item_id"
      ],
      "msg": "Input should be a valid integer, unable to parse string as an integer",
      "input": "foo"
    }
  ]
}
```

porque el parámetro de path `item_id` tenía un valor de `"foo"`, que no es un `int`.

     * Includes reference counting for multi-threaded access tracking.
     */
    public static class StatsObject extends LinkedHashMap<String, Long> {
        /** Serial version UID for serialization. */
        private static final long serialVersionUID = 1L;

        /** Atomic counter for tracking reference count across multiple threads. */
        protected final AtomicInteger count;

    }

    @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;
  }

  /**
   * Returns a synchronized (thread-safe) table backed by the specified table. In order to guarantee
   * serial access, it is critical that <b>all</b> access to the backing table is accomplished
   * through the returned table.
   *
   * <p>It is imperative that the user manually synchronize on the returned table when accessing any

  public static final byte DC1 = 17; // aka XON

  /**
   * Transmission On: Although originally defined as DC1, this ASCII control character is now better
   * known as the XON code used for software flow control in serial communications. The main use is
   * restarting the transmission after the communication has been stopped by the XOFF control code.
   *
   * @since 8.0
   */
  public static final byte XON = 17; // aka DC1

 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 * @since 2.0
 */
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableMultiset<E> extends ImmutableCollection<E> implements Multiset<E> {

  /**

 *
 * @see ImmutableMap
 * @see ImmutableSet
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
public abstract class ImmutableList<E> extends ImmutableCollection<E>
    implements List<E>, RandomAccess {

  /**

 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @since 2.0
 */
@DoNotMock("Use ImmutableList.of or another implementation")
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
// TODO(kevinb): I think we should push everything down to "BaseImmutableCollection" or something,

 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @since 2.0
 */
@DoNotMock("Use ImmutableList.of or another implementation")
@GwtCompatible
@SuppressWarnings("serial") // we're overriding default serialization
// TODO(kevinb): I think we should push everything down to "BaseImmutableCollection" or something,

{* ../../docs_src/python_types/tutorial001.py hl[2] *}

### Edítalo

Es un programa muy simple.

Pero ahora imagina que lo escribieras desde cero.

En algún momento habrías empezado la definición de la función, tenías los parámetros listos...

Pero luego tienes que llamar "ese método que convierte la primera letra a mayúscula".

¿Era `upper`? ¿Era `uppercase`? `first_uppercase`? `capitalize`?

  public ImmutableMultiset<K> keys() {
    return (ImmutableMultiset<K>) super.keys();
  }

  @Override
  ImmutableMultiset<K> createKeys() {
    return new Keys();
  }

  @SuppressWarnings("serial") // Uses writeReplace, not default serialization
  @WeakOuter
  private final class Keys extends ImmutableMultiset<K> {
    @Override
    public boolean contains(@Nullable Object object) {