assertThrows(IllegalArgumentException.class, () -> Range.atLeast(2).gap(Range.atLeast(1)));

    assertThrows(IllegalArgumentException.class, () -> Range.atMost(1).gap(Range.atMost(2)));

    assertThrows(IllegalArgumentException.class, () -> Range.atMost(2).gap(Range.atMost(1)));
  }

  public void testGap_connectedAdjacentYieldsEmpty() {
    Range<Integer> range = Range.open(3, 4);

    assertEquals(set, Sets.subSet(set, Range.lessThan(20)));

    assertEquals(empty, Sets.subSet(set, Range.atMost(0)));
    assertEquals(ImmutableSortedSet.of(2, 4), Sets.subSet(set, Range.atMost(4)));
    assertEquals(ImmutableSortedSet.of(2, 4, 6), Sets.subSet(set, Range.atMost(7)));
    assertEquals(set, Sets.subSet(set, Range.atMost(20)));
  }

  @GwtIncompatible // NavigableSet
  public void testSubSet_unboundedRange() {

/// tip

    * An example is `404`, for a "Not Found" response.
    * For generic errors from the client, you can just use `400`.
* `500` and above are for server errors. You almost never use them directly. When something goes wrong at some part in your application code, or server, it will automatically return one of these status codes.

/// tip

A **request** body is data sent by the client to your API. A **response** body is the data your API sends to the client.

Your API almost always has to send a **response** body. But clients don't necessarily need to send **request bodies** all the time, sometimes they only request a path, maybe with some query parameters, but don't send a body.

## Recap

With what you have seen up to now, you can set up a secure **FastAPI** application using standards like OAuth2 and JWT.

In almost any framework handling the security becomes a rather complex subject quite quickly.

///

By doing that, your editor can provide support even while processing items from the list:

<img src="/img/python-types/image05.png">

Without types, that's almost impossible to achieve.

Notice that the variable `item` is one of the elements in the list `items`.

And still, the editor knows it is a `str`, and provides support for that.

#### Tuple and Set

    return new ArrayList<>(initialArraySize);
  }

  /**
   * Creates an {@code ArrayList} instance to hold {@code estimatedSize} elements, <i>plus</i> an
   * unspecified amount of padding; you almost certainly mean to call {@link
   * #newArrayListWithCapacity} (see that method for further advice on usage).
   *
   * <p><b>Note:</b> This method will soon be deprecated. Even in the rare case that you do want