```

////

## Set types

But then we think about it, and realize that tags shouldn't repeat, they would probably be unique strings.

And Python has a special data type for sets of unique items, the `set`.

Then we can declare `tags` as a set of strings:

//// tab | Python 3.10+

```Python hl_lines="12"
{!> ../../docs_src/body_nested_models/tutorial003_py310.py!}
```

////

func (list *TargetList) Exists(id TargetID) bool {
	list.RLock()
	defer list.RUnlock()

	_, found := list.targets[id]
	return found
}

// TargetIDResult returns result of Remove/Send operation, sets err if
// any for the associated TargetID
type TargetIDResult struct {
	// ID where the remove or send were initiated.
	ID TargetID
	// Stores any error while removing a target or while sending an event.
	Err error

				return "127.0.0.1"
			}
			return ip
		})
		nonInterIPV4s = mustGetLocalIP4().Intersection(hostIPs)
	}
	nonInterIPV6s := mustGetLocalIP6().Intersection(hostIPs)

	// If intersection of two IP sets is not empty, then the host is localhost.
	isLocalv4 := !nonInterIPV4s.IsEmpty()
	isLocalv6 := !nonInterIPV6s.IsEmpty()
	if port != "" {
		return (isLocalv4 || isLocalv6) && (port == localPort), nil
	}

		case "expect":
			// Golang http server strips off 'Expect' header, if the
			// client sent this as part of signed headers we need to
			// handle otherwise we would see a signature mismatch.
			// `aws-cli` sets this as part of signed headers.
			//
			// According to
			// http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.20
			// Expect header is always of form:
			//

		uploadID          string // uploadID of the transaction.
		invalidPartNumber bool   // Sets an invalid multipart.
		maximumPartNumber bool   // Sets a maximum parts.
		accessKey         string
		secretKey         string
		// expected output.
		expectedRespStatus int
	}{

        if (systemProperties != null) {
            this.systemProperties = new Properties();
            // avoid concurrent modification if someone else sets/removes an unrelated system property
            synchronized (systemProperties) {
                this.systemProperties.putAll(systemProperties);
            }
        } else {
            this.systemProperties = null;

   *
   * <ul>
   *   <li>A and B have equal {@link #isDirected() directedness}.
   *   <li>A and B have equal {@link #nodes() node sets}.
   *   <li>A and B have equal {@link #edges() edge sets}.
   *   <li>The {@link #edgeValue(N, N) value} of a given edge is the same in both A and B.
   * </ul>
   *

		size: size,
	}
}

// NewBuffer returns a new RingBuffer whose buffer is provided.
func NewBuffer(b []byte) *RingBuffer {
	return &RingBuffer{
		buf:  b,
		size: len(b),
	}
}

// SetBlocking sets the blocking mode of the ring buffer.
// If block is true, Read and Write will block when there is no data to read or no space to write.
// If block is false, Read and Write will return ErrIsEmpty or ErrIsFull immediately.

   *
   * <ul>
   *   <li>A and B have equal {@link #isDirected() directedness}.
   *   <li>A and B have equal {@link #nodes() node sets}.
   *   <li>A and B have equal {@link #edges() edge sets}.
   * </ul>
   *
   * <p>Graph properties besides {@link #isDirected() directedness} do <b>not</b> affect equality.

import static com.google.common.collect.Iterators.singletonIterator;
import static com.google.common.collect.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.collect.Sets.newHashSet;
import static com.google.common.collect.testing.IteratorFeature.UNMODIFIABLE;
import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;