`Optional[Something]` là một cách viết ngắn gọn của `Union[Something, None]`, chúng là tương đương nhau.

Điều này cũng có nghĩa là trong Python 3.10, bạn có thể sử dụng `Something | None`:

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

    // Read a token68, a sequence of parameters, or nothing.
    val commaPrefixed = skipCommasAndWhitespace()
    peek = readToken()
    if (peek == null) {
      if (!exhausted()) return // Expected a token; got something else.
      result.add(Challenge(schemeName, emptyMap()))
      return
    }

    var eqCount = skipAll('='.code.toByte())
    val commaSuffixed = skipCommasAndWhitespace()

  // HashCode on an existing OutputStream, compared to creating a separate OutputStream that could
  // be (optionally) be combined with another if needed (with something like
  // MultiplexingOutputStream).
  public HashingOutputStream(HashFunction hashFunction, OutputStream out) {
    super(checkNotNull(out));
    this.hasher = checkNotNull(hashFunction.newHasher());
  }

            throws ProjectBuildingException;

    // TODO this is only to provide a project for plugins that don't need a project to execute but need some
    // of the values from a MavenProject. Ideally this should be something internal and nothing outside Maven
    // would ever need this so it should not be exposed in a public API
    MavenProject buildStandaloneSuperProject(ProjectBuilderConfiguration configuration) throws ProjectBuildingException;

   *
   * ```
   * [5] EXPLICIT UTF8String
   * ```
   *
   * @param forceConstructed non-null to set the constructed bit to the specified value, even if the
   *     writing process sets something else. This is used to encode SEQUENCES in values that are
   *     declared to have non-constructed values, like OCTET STRING values.
   */
  @Suppress("UNCHECKED_CAST") // read() produces a single element of the expected type.

   * String.class}, then {@code new TypeResolver().where(formal, actual)} will {@linkplain
   * #resolveType resolve} {@code ParameterizedType List<T>} to {@code List<String>}, and resolve
   * {@code Map<T, Something>} to {@code Map<String, Something>} etc. Similarly, {@code formal} and
   * {@code actual} can be {@code Map<K, V>} and {@code Map<String, Integer>} respectively, or they

`Optional[Something]` é na verdade um atalho para `Union[Something, None]`, eles são equivalentes.

Isso também significa que no Python 3.10, você pode utilizar `Something | None`:

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

////

   * someone still manages to pass null, let's continue to have the method work.
   *
   * (PatternFilenameFilter is of course one of those classes that shouldn't be a publicly visible
   * class to begin with but rather something returned from a static factory method whose declared
   * return type is plain FilenameFilter. If we made such a change, then the annotation we choose

    assertHash(expected, murmur3_32_fixed().newHasher().putBytes(string.getBytes(charset)).hash());
  }

  private boolean allBmp(String string) {
    // Ordinarily we'd use something like i += Character.charCount(string.codePointAt(i)) here. But
    // we can get away with i++ because the whole point of this method is to return false if we find
    // a code point that doesn't fit in a char.

              } catch (Throwable t) {
                // (including CancellationException and sneaky checked exception)
                // The task is presumably done, run the listeners.
                // TODO(cpovirk): Do *something* in case of Error (and maybe
                // non-CancellationException, non-ExecutionException exceptions)?
              }
              executionList.execute();
            });
      }
    }
  }