This is just a **quick tutorial / refresher** about Python type hints. It covers only the minimum necessary to use them with **FastAPI**... which is actually very little.

**FastAPI** is all based on these type hints, they give it many advantages and benefits.

But even if you never use **FastAPI**, you would benefit from learning a bit about them.

/// note

   * input byte array {@code {0x54, 0x32}} would yield the {@code char} value {@code '\\u5432'}.
   *
   * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that library exposes much more
   * flexibility at little cost in readability.
   *
   * @throws IllegalArgumentException if {@code bytes} has fewer than 2 elements
   */
  @GwtIncompatible // doesn't work
  public static char fromByteArray(byte[] bytes) {

   * input byte array {@code {0x54, 0x32}} would yield the {@code short} value {@code 0x5432}.
   *
   * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that library exposes much more
   * flexibility at little cost in readability.
   *
   * @throws IllegalArgumentException if {@code bytes} has fewer than 2 elements
   */
  @GwtIncompatible // doesn't work
  public static short fromByteArray(byte[] bytes) {

   * input byte array {@code {0x54, 0x32}} would yield the {@code short} value {@code 0x5432}.
   *
   * <p>Arguably, it's preferable to use {@link java.nio.ByteBuffer}; that library exposes much more
   * flexibility at little cost in readability.
   *
   * @throws IllegalArgumentException if {@code bytes} has fewer than 2 elements
   */
  @GwtIncompatible // doesn't work
  public static short fromByteArray(byte[] bytes) {

 * number of concurrent accesses instead of the rate (note though that concurrency and rate are
 * closely related, e.g. see <a href="http://en.wikipedia.org/wiki/Little%27s_law">Little's
 * Law</a>).
 *
 * <p>A {@code RateLimiter} is defined primarily by the rate at which permits are issued. Absent
 * additional configuration, permits will be distributed at a fixed rate, defined in terms of

If you are paying for 3 servers but you are using only a little bit of their RAM and CPU, you are probably **wasting money** 💸, and probably **wasting server electric power** 🌎, etc.

      System.arraycopy(hash, 0, hashes, i * hashBytes, hash.length);
    }

    // Then hash the result array
    byte[] result = hashFunction.hash(hashes, 0);

    // interpreted in little-endian order.
    int verification = Integer.reverseBytes(Ints.fromByteArray(result));

    if (expected != verification) {
      throw new AssertionError(
          "Expected: "

    }
  }

  /**
   * Returns an address from a <b>little-endian ordered</b> byte array (the opposite of what {@link
   * InetAddress#getByAddress} expects).
   *
   * <p>IPv4 address byte array must be 4 bytes long and IPv6 byte array must be 16 bytes long.
   *
   * @param addr the raw IP address in little-endian byte order
   * @return an InetAddress object created from the raw IP address

**Typer** is FastAPI's little sibling. And it's intended to be the **FastAPI of CLIs**. ⌨️ 🚀

## Requirements

FastAPI stands on the shoulders of giants:

    if (expected.equals(in)) {
      assertSame(in, out);
    } else {
      assertEquals(expected, out);
    }
  }

  // Test collapse() a little differently than the rest, as we really want to
  // cover lots of different configurations of input text
  public void testCollapse() {
    // collapsing groups of '-' into '_' or '-'
    doTestCollapse("-", "_");