# Using Dataclasses

FastAPI is built on top of **Pydantic**, and I have been showing you how to use Pydantic models to declare requests and responses.

But FastAPI also supports using <a href="https://docs.python.org/3/library/dataclasses.html" class="external-link" target="_blank">`dataclasses`</a> the same way:

{* ../../docs_src/dataclasses/tutorial001.py hl[1,7:12,19:20] *}

multicore CPUs, general purpose GPUs, and custom-designed ASICs known as Tensor Processing Units (TPUs). This architecture gives flexibility to the application developer, whereas in previous “parameter server” designs the management of shared state is built into the system, TensorFlow enables developers to experiment with novel optimizations and training algorithms. TensorFlow supports a variety of applications, with a focus on training and inference on deep neural networks. Several Google services use...

* API keys in:
    * Headers.
    * Query parameters.
    * Cookies, etc.

Plus all the security features from Starlette (including **session cookies**).

All built as reusable tools and components that are easy to integrate with your systems, data stores, relational and NoSQL databases, etc.

### Dependency Injection

 * [Coil](https://github.com/coil-kt/coil): An image loading library for Android backed by Kotlin Coroutines.
 * [Communicator](https://github.com/Taig/Communicator): An OkHttp wrapper for Scala built with Android in mind.
 * [Cronet Transport for OkHttp](https://github.com/google/cronet-transport-for-okhttp): A HTTP3 ready transport layer for OkHttp on Android, based on Chromium network stack.

		}
	}

	return locked
}

const (
	lockRetryInterval = 50 * time.Millisecond
)

// lockLoop will acquire either a read or a write lock
//
// The call will block until the lock is granted using a built-in
// timing randomized back-off algorithm to try again until successful
func (lm *LRWMutex) lockLoop(ctx context.Context, id, source string, timeout time.Duration, isWriteLock bool) (locked bool) {

   * for a given key in sorted order, but it need not expose the <i>keys</i> in sorted order.
   * Individual {@code SortedSetMultimap} implementations, like those built with {@link
   * MultimapBuilder#treeKeys()}, may make additional guarantees.
   */
  @Override
  Map<K, Collection<V>> asMap();

  /**

 * }, executor);
 * }</pre>
 *
 * <h3>How to get an instance</h3>
 *
 * <p>We encourage you to return {@code ListenableFuture} from your methods so that your users can
 * take advantage of the {@linkplain Futures utilities built atop the class}. The way that you will
 * create {@code ListenableFuture} instances depends on how you currently create {@code Future}
 * instances:
 *
 * <ul>

}

// APIGroupDiscoveryList is a resource containing a list of APIGroupDiscovery.
// This is one of the types able to be returned from the /api and /apis endpoint and contains an aggregated
// list of API resources (built-ins, Custom Resource Definitions, resources from aggregated servers)
// that a cluster supports.
message APIGroupDiscoveryList {

   * for a given key in sorted order, but it need not expose the <i>keys</i> in sorted order.
   * Individual {@code SortedSetMultimap} implementations, like those built with {@link
   * MultimapBuilder#treeKeys()}, may make additional guarantees.
   */
  @Override
  Map<K, Collection<V>> asMap();

  /**

		count++
	}
	if err := scanner.Err(); err != nil {
		fmt.Fprintln(os.Stderr, "reading input:", err)
	}
	fmt.Printf("%d\n", count)
	// Output: 15
}

// Use a Scanner with a custom split function (built by wrapping ScanWords) to validate
// 32-bit decimal input.
func ExampleScanner_custom() {
	// An artificial input source.
	const input = "1234 5678 1234567901234567890"