`Optional[Something]` is actually a shortcut for `Union[Something, None]`, they are equivalent.

This also means that in Python 3.10, you can use `Something | None`:

//// tab | Python 3.10+

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

////

    CharSource concatenated = CharSource.concat(cycle);

    String expected = "abcdabcd";

    // read the first 8 chars manually, since there's no equivalent to ByteSource.slice
    // TODO(cgdecker): Add CharSource.slice?
    StringBuilder builder = new StringBuilder();
    Reader reader = concatenated.openStream(); // no need to worry about closing

  RangeMap<K, V> subRangeMap(Range<K> range);

  /**
   * Returns {@code true} if {@code obj} is another {@code RangeMap} that has an equivalent {@link
   * #asMapOfRanges()}.
   */
  @Override
  boolean equals(@Nullable Object o);

  /** Returns {@code asMapOfRanges().hashCode()}. */
  @Override
  int hashCode();

    // hashcodes from non-overlapping hash computations
    HashCode expected1 = randomHash(hashFunction, new Random(1L), numActions);
    HashCode expected2 = randomHash(hashFunction, new Random(2L), numActions);

    // equivalent, but overlapping, computations (should produce the same results as above)
    Random random1 = new Random(1L);
    Random random2 = new Random(2L);
    Hasher hasher1 = hashFunction.newHasher();

     */
    public String getPassword() {
        return password;
    }

    /**
     * Return the domain and username in the format:
     * {@code domain\\username}. This is equivalent to {@code toString()}.
     */
    @Override
    public String getName() {
        final boolean d = domain.length() > 0 && !domain.equals("?");
        return d ? domain + "\\" + username : username;
    }

JetBrains [is working on][kotlin_sams] SAM conversions of Kotlin interfaces. Expect it in a future
release of the Kotlin language.


Companion Imports
-----------------

The equivalent of static methods in Java is companion object functions in Kotlin. The bytecode is
the same but `.kt` files now need `Companion` in the import.

This works with OkHttp 3.x:

```kotlin

    /**
     * Returns {@code true} if there is at least one problem collected with severity equal or more severe than
     * {@link org.apache.maven.api.services.BuilderProblem.Severity#WARNING}. This check is logically equivalent
     * to "is there any problem reported?", given warning is the lowest severity.
     */
    default boolean hasWarningProblems() {
        return hasProblemsFor(BuilderProblem.Severity.WARNING);
    }

    /**

}

var errorRune = []byte(string(utf8.RuneError))

// ScanRunes is a split function for a [Scanner] that returns each
// UTF-8-encoded rune as a token. The sequence of runes returned is
// equivalent to that from a range loop over the input as a string, which
// means that erroneous UTF-8 encodings translate to U+FFFD = "\xef\xbf\xbd".
// Because of the Scan interface, this makes it impossible for the client to

     * or
     * proto:server[key1=val1,key2=val2]
     * or
     * proto:[key1=val1,key2=val2]
     *
     * If a key is absent it is assumed to be 'endpoint'. Thus the
     * following are equivalent:
     * proto:\\ts0.win.net[endpoint=\pipe\srvsvc]
     * proto:ts0.win.net[\pipe\srvsvc]
     *
     * If the server is absent it is set to "127.0.0.1"
     */
    /**

  }

  /**
   * Returns a predicate that evaluates to {@code true} if the {@code CharSequence} being tested
   * contains any match for the given regular expression pattern. The test used is equivalent to
   * {@code Pattern.compile(pattern).matcher(arg).find()}
   *
   * @throws IllegalArgumentException if the pattern is invalid
   * @since 3.0
   */