@app.get("/items/")
def read_items():
    data = some_blocking_library.fetch_items()
    return data
```

In case of doubt, or by default, use regular `def` functions, those will be run in a threadpool so they don't block the event loop.

The same rules apply to dependencies.

Make sure blocking code is not run inside of `async` functions. The logic will work, but will damage the performance heavily.

   * iterable}. The iterator's {@code hasNext()} method returns {@code true} until {@code iterable}
   * is empty.
   *
   * <p><b>Warning:</b> Typical uses of the resulting iterator may produce an infinite loop. You
   * should use an explicit {@code break} or be certain that you will eventually remove all the
   * elements.
   *
   * <p>To cycle over the iterable {@code n} times, use the following: {@code

{* ../../docs_src/query_params_str_validations/tutorial015_an_py310.py ln[16:19] hl[17] *}

#### A Random Item { #a-random-item }

With `data.items()` we get an <dfn title="Something we can iterate on with a for loop, like a list, set, etc.">iterable object</dfn> with tuples containing the key and value for each dictionary item.

We convert this iterable object into a proper `list` with `list(data.items())`.

                                                        TF_Status* status);

// Some TF ops need a step container to be set to limit the lifetime of some
// resources (mostly TensorArray and Stack, used in while loop gradients in
// graph mode). Calling this on a context tells it to start a step.
TF_CAPI_EXPORT extern void TFE_ContextStartStep(TFE_Context* ctx);

// Ends a step. When there is no active step (that is, every started step has

                    String escaped = warning.replaceAll('"', '\\\\"')
                    /* Quote the warning in case it starts with [ which makes
                     * it look too much like an array. */
                    current.println("         - \"$escaped\"")
                }
            }
            current.println("      raw:")
            current.println("        method: $method")

   * #descendingMap}. (The {@link StandardDescendingMap} implementation implements {@code
   * navigableKeySet} on its own, so as not to cause an infinite loop.) If you override {@code
   * descendingMap}, you may wish to override {@code descendingKeySet} to forward to this
   * implementation.
   */
  protected NavigableSet<K> standardDescendingKeySet() {

      this.countMap = countMap;
    }

    // Query Operations

    /**
     * Returns the number of occurrences of {@code element} in this multiset.
     *
     * @param element the element to look for
     * @return the nonnegative number of occurrences of the element
     */
    @Override
    public int count(@Nullable Object element) {
      try {
        return unbox(countMap.get(element));

   * #descendingMap}. (The {@link StandardDescendingMap} implementation implements {@code
   * navigableKeySet} on its own, so as not to cause an infinite loop.) If you override {@code
   * descendingMap}, you may wish to override {@code descendingKeySet} to forward to this
   * implementation.
   */
  protected NavigableSet<K> standardDescendingKeySet() {

// initDataScanner will start the scanner in the background.
func initDataScanner(ctx context.Context, objAPI ObjectLayer) {
	go func() {
		r := rand.New(rand.NewSource(time.Now().UnixNano()))
		// Run the data scanner in a loop
		for {
			runDataScanner(ctx, objAPI)
			duration := max(time.Duration(r.Float64()*float64(scannerCycle.Load())),
				// Make sure to sleep at least a second to avoid high CPU ticks.
				time.Second)

	// already have the sizes from the central directory so we can
	// just ignore these.

	return nil
}

func readDirectoryEnd(r io.ReaderAt, size int64) (dir *directoryEnd, baseOffset int64, err error) {
	// look for directoryEndSignature in the last 1k, then in the last 65k
	var buf []byte
	var directoryEndOffset int64
	for i, bLen := range []int64{1024, 65 * 1024} {
		if bLen > size {
			bLen = size
		}