static {
        // Those two public constants are initialized here, as they need all the private constants
        // above to be initialized first, but the code style imposes the public constants to be
        // defined above the private ones...
        OS_FAMILY = getOsFamily();
        IS_WINDOWS = isFamily(FAMILY_WINDOWS);
    }

    private Os() {}

Now that we have seen how to use `Path` and `Query`, let's see more advanced uses of request body declarations.

## Mix `Path`, `Query` and body parameters { #mix-path-query-and-body-parameters }

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

And you can also declare body parameters as optional, by setting the default to `None`:

    }

    // just for testing
    private <T> Prepender() {
      this(null, 0);
    }

    static <T> Iterable<String> prepend(@NotBlank String first, Iterable<String> tail) {
      return Iterables.concat(ImmutableList.of(first), tail);
    }

    Iterable<String> prepend(Iterable<String> tail)
        throws IllegalArgumentException, NullPointerException {

        // Test with no matching headers
        String result = virtualHostHelper.processVirtualHost(s -> "processed_" + s, "default");
        assertEquals("default", result);

        // Test with matching first header
        request.addHeader("Host", "example.com");
        result = virtualHostHelper.processVirtualHost(s -> "processed_" + s, "default");
        assertEquals("processed_site1", result);

    stream.defaultWriteObject();
    stream.writeObject(type);
    Serialization.writeMultiset(this, stream);
  }

  /**
   * @serialData the {@code Class<E>} for the enum type, the number of distinct elements, the first
   *     element, its count, the second element, its count, and so on
   */
  @GwtIncompatible // java.io.ObjectInputStream
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {

		} else {
			builder.WriteByte('@')
			builder.WriteString(string(name))
		}
	}
}

// processValue handles different value types appropriately for SQL parameter binding
// It checks for driver.Valuer first, then handles slices/arrays, and finally adds single values
func processValue(builder Builder, value interface{}) {
	if _, ok := value.(driver.Valuer); ok {
		builder.AddVar(builder, value)
		return
	}

	"github.com/minio/minio/internal/hash/sha256"
	"golang.org/x/crypto/blake2b"

	xioutil "github.com/minio/minio/internal/ioutil"
	"github.com/minio/minio/internal/logger"
)

// magic HH-256 key as HH-256 hash of the first 100 decimals of π as utf-8 string with a zero key.
var magicHighwayHash256Key = []byte("\x4b\xe7\x34\xfa\x8e\x23\x8a\xcd\x26\x3e\x83\xe6\xbb\x96\x85\x52\x04\x0f\x93\x5d\xa3\x9f\x44\x14\x97\xe0\x9d\x13\x22\xde\x36\xa0")

    ExecutorService blocked = newCachedThreadPool();
    Future<?> first = blocked.submit(() -> executor.execute(Runnables.doNothing()));
    future.get(10, SECONDS);
    assertThrows(RejectedExecutionException.class, () -> executor.execute(Runnables.doNothing()));
    latch.countDown();
    ExecutionException expected =
        assertThrows(ExecutionException.class, () -> first.get(10, SECONDS));

   * there are no elements left in the iteration. Failure to do so could result in an infinite loop.
   *
   * <p>The initial invocation of {@link #hasNext()} or {@link #next()} calls this method, as does
   * the first invocation of {@code hasNext} or {@code next} following each successful call to
   * {@code next}. Once the implementation either invokes {@code endOfData} or throws an exception,

  return any(
      _current_file_location.startswith(dir_) for dir_ in _site_packages_dirs)

if _running_from_pip_package():
  # TODO(gunan): Add sanity checks to loaded modules here.

  # Load first party dynamic kernels.
  _tf_dir = _os.path.dirname(_current_file_location)
  _kernel_dir = _os.path.join(_tf_dir, "core", "kernels")
  if _os.path.exists(_kernel_dir):
    _ll.load_library(_kernel_dir)