package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;
import java.util.Iterator;

/**
 * Creates iterators to be tested.
 *
 * @param <E> the element type of the iterator.
 * @author George van den Driessche
 */
@GwtCompatible
public interface TestIteratorGenerator<E> {
  Iterator<E> get();

  }

  public void testIteratorPastEndException() {
    MinMaxPriorityQueue<Integer> mmHeap = MinMaxPriorityQueue.create();
    mmHeap.addAll(Lists.newArrayList(1, 2));
    Iterator<Integer> it = mmHeap.iterator();
    assertTrue("Iterator has reached end prematurely", it.hasNext());
    it.next();
    it.next();
    assertThrows(NoSuchElementException.class, () -> it.next());
  }

Details about the `async def` syntax for *path operation functions* and some background about asynchronous code, concurrency, and parallelism.

## In a hurry?

<abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>

If you are using third party libraries that tell you to call them with `await`, like:

```Python
results = await some_library()
```

Then, declare your *path operation functions* with `async def` like:

import static org.codelibs.core.misc.AssertionUtil.assertArgumentNotNull;

import java.util.Iterator;
import java.util.NoSuchElementException;

import org.codelibs.core.exception.ClUnsupportedOperationException;
import org.codelibs.core.message.MessageFormatter;

/**
 * クラスの継承階層を親クラスに向かって反復する{@link Iterator}です。
 * <p>
 * 次のように使います．
 * </p>
 *
 * <pre>
 * import static org.codelibs.core.lang.ClassIterator.*;

    }

    private boolean equals(Collection<Exclusion> ce1, Collection<Exclusion> ce2) {
        if (ce1.size() == ce2.size()) {
            Iterator<Exclusion> i1 = ce1.iterator();
            Iterator<Exclusion> i2 = ce2.iterator();
            while (i1.hasNext() && i2.hasNext()) {
                if (!equals(i1.next(), i2.next())) {
                    return false;
                }
            }

    StringSubscriber s2 = new StringSubscriber();
    ObjectSubscriber o1 = new ObjectSubscriber();

    Iterator<Subscriber> empty = registry.getSubscribers("");
    assertFalse(empty.hasNext());

    empty = registry.getSubscribers("");

    registry.register(s1);
    assertFalse(empty.hasNext());

    Iterator<Subscriber> one = registry.getSubscribers("");
    assertEquals(s1, one.next().target);

  private Dispatcher dispatcher;

  public void testPerThreadQueuedDispatcher() {
    dispatcher = Dispatcher.perThreadDispatchQueue();
    dispatcher.dispatch(1, integerSubscribers.iterator());

    assertThat(dispatchedSubscribers)
        .containsExactly(
            i1,
            i2,
            i3, // Integer subscribers are dispatched to first.
            s1,

      return standardSetCount(element, count);
    }

    @Override
    public Set<T> elementSet() {
      return new StandardElementSet();
    }

    @Override
    public Iterator<T> iterator() {
      return standardIterator();
    }

    @Override
    public boolean isEmpty() {
      return standardIsEmpty();
    }

    @Override
    public int size() {

  TF_AbstractTensor* at =
      TF_CreateAbstractTensorFromEagerTensor(t, status.get());
  ASSERT_EQ(TF_OK, TF_GetCode(status.get())) << TF_Message(status.get());

  // Build an abstract operation.
  auto* op = TF_NewAbstractOp(ctx);
  TF_AbstractOpSetOpType(op, "Add", status.get());
  ASSERT_EQ(TF_OK, TF_GetCode(status.get())) << TF_Message(status.get());

  // Build inputs and outputs.

# Response Model - Return Type

You can declare the type used for the response by annotating the *path operation function* **return type**.

You can use **type annotations** the same way you would for input data in function **parameters**, you can use Pydantic models, lists, dictionaries, scalar values like integers, booleans, etc.

//// tab | Python 3.10+

```Python hl_lines="16  21"
{!> ../../docs_src/response_model/tutorial001_01_py310.py!}
```