def __iter__(self) -> Generator[str, None, None]:
        for item in self.data:
            if self.open:
                yield item
            else:
                raise ValueError("Session closed")


@contextmanager
def acquire_session() -> Generator[Session, None, None]:
    session = Session()
    try:
        yield session
    finally:
        session.open = False

  }

  public void testCopyToAppendable_doesNotCloseIfWriter() throws IOException {
    TestWriter writer = new TestWriter();
    assertFalse(writer.closed());
    source.copyTo(writer);
    assertFalse(writer.closed());
  }

  public void testClosesOnErrors_copyingToCharSinkThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, WRITE_THROWS, CLOSE_THROWS)) {

  }

  @Override
  public String toString() {
    return comparator
        + ":"
        + (lowerBoundType == CLOSED ? '[' : '(')
        + (hasLowerBound ? lowerEndpoint : "-\u221e")
        + ','
        + (hasUpperBound ? upperEndpoint : "\u221e")
        + (upperBoundType == CLOSED ? ']' : ')');
  }

  @Nullable T getLowerEndpoint() {
    return lowerEndpoint;
  }

  }

  @Override
  public String toString() {
    return comparator
        + ":"
        + (lowerBoundType == CLOSED ? '[' : '(')
        + (hasLowerBound ? lowerEndpoint : "-\u221e")
        + ','
        + (hasUpperBound ? upperEndpoint : "\u221e")
        + (upperBoundType == CLOSED ? ']' : ')');
  }

  @Nullable T getLowerEndpoint() {
    return lowerEndpoint;
  }

  }

  public void testCopyToAppendable_doesNotCloseIfWriter() throws IOException {
    TestWriter writer = new TestWriter();
    assertFalse(writer.closed());
    source.copyTo(writer);
    assertFalse(writer.closed());
  }

  public void testClosesOnErrors_copyingToCharSinkThatThrows() {
    for (TestOption option : EnumSet.of(OPEN_THROWS, WRITE_THROWS, CLOSE_THROWS)) {

 *   public static Book paperback(String title) {...}
 * }
 * </pre>
 *
 * <p>please use {@link ClassSanityTester#forAllPublicStaticMethods}.
 *
 * <p>If not all classes on the classpath should be covered, {@link #ignoreClasses} can be used to
 * exclude certain classes. As a special case, classes with an underscore in the name (like {@code
 * AutoValue_Foo}) can be excluded using <code>ignoreClasses({@link #UNDERSCORE_IN_NAME})</code>.

        }
        this.dns = dns
      }

    /**
     * Sets the HTTP proxy that will be used by connections created by this client. This takes
     * precedence over [proxySelector], which is only honored when this proxy is null (which it is
     * by default). To disable proxy use completely, call `proxy(Proxy.NO_PROXY)`.
     */
    fun proxy(proxy: Proxy?) =
      apply {
        if (proxy != this.proxy) {

     * @return output stream, needs to be closed when finished
     * @throws CIFSException if an error occurs accessing the resource
     */
    OutputStream openOutputStream(boolean append) throws CIFSException;

    /**
     * Opens an output stream writing to the file (truncating, write only, sharable)
     *
     * @return output stream, needs to be closed when finished

        private final int id;
        private boolean closed = false;

        public CloseableTestComponent() {
            this.id = instanceCounter.incrementAndGet();
        }

        public int getId() {
            return id;
        }

        public boolean isClosed() {
            return closed;
        }

        @Override

```console
$ uvicorn main:app --reload

<span style="color: green;">INFO</span>:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
<span style="color: green;">INFO</span>:     Started reloader process [28720]
<span style="color: green;">INFO</span>:     Started server process [28722]
<span style="color: green;">INFO</span>:     Waiting for application startup.
<span style="color: green;">INFO</span>:     Application startup complete.
```