```Python hl_lines="14"
{!../../docs_src/handling_errors/tutorial002.py!}
```

## Install custom exception handlers

You can add custom exception handlers with <a href="https://www.starlette.io/exceptions/" class="external-link" target="_blank">the same exception utilities from Starlette</a>.

Let's say you have a custom exception `UnicornException` that you (or a library you use) might `raise`.

 *
 * <ul>
 *   <li>example.com
 *   <li>example.com:80
 *   <li>192.0.2.1
 *   <li>192.0.2.1:80
 *   <li>[2001:db8::1] - {@link #getHost()} omits brackets
 *   <li>[2001:db8::1]:80 - {@link #getHost()} omits brackets
 *   <li>2001:db8::1 - Use {@link #requireBracketsForIPv6()} to prohibit this
 * </ul>
 *
 * <p>Note that this is not an exhaustive list, because these methods are only concerned with

 * }
 * </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>.
 *

import java.util.Set;
import javax.annotation.CheckForNull;

/**
 * An implementation of {@code RangeMap} based on a {@code TreeMap}, supporting all optional
 * operations.
 *
 * <p>Like all {@code RangeMap} implementations, this supports neither null keys nor null values.
 *
 * @author Louis Wasserman
 * @since 14.0
 */
@SuppressWarnings("rawtypes") // https://github.com/google/guava/issues/989

in Source Code form that contains any contents of the Program. Modified
Works shall not include works that contain only declarations,
interfaces, types, classes, structures, or files of the Program solely
in each case in order to link to, bind by name, or subclass the Program
or Modified Works thereof.

"Distribute" means the acts of a) distributing or b) making available
in any manner that enables the transfer of a copy.

   * name as one of the public methods of {@link TypeVariableImpl}, the proxy calls the same method
   * on its instance of {@code TypeVariableImpl}. Otherwise it throws {@link
   * UnsupportedOperationException}; this should only apply to {@code getAnnotatedBounds()}. This
   * does mean that users on Java 8 who obtain an instance of {@code TypeVariable} from {@link

   * State#RUNNING}. Services that need to cancel startup work can override {@link #doCancelStart}.
   */
  @ForOverride
  protected abstract void doStop();

  /**
   * This method is called by {@link #stopAsync} when the service is still starting (i.e. {@link
   * #startAsync} has been called but {@link #notifyStarted} has not). Subclasses can override the

You can use OAuth2 scopes directly with **FastAPI**, they are integrated to work seamlessly.

This would allow you to have a more fine-grained permission system, following the OAuth2 standard, integrated into your OpenAPI application (and the API docs).

OAuth2 with scopes is the mechanism used by many big authentication providers, like Facebook, Google, GitHub, Microsoft, Twitter, etc. They use it to provide specific permissions to users and applications.

  AbstractContext* ctx_;
};

// Returns the number of elements in the gradient tensor.
int64_t TapeVSpace::NumElements(AbstractTensorHandle* tensor) const {
  // TODO(srbs): It seems like this is used only for performance optimization
  // and not for correctness. The only downside of keeping this 1 seems to be
  // that the gradient accumulation is unbounded and we will never

// calculation repeatedly under hash.Reader.
type Options struct {
	MD5Hex     string
	SHA256Hex  string
	Size       int64
	ActualSize int64
	DisableMD5 bool
	ForceMD5   []byte
}

// NewReaderWithOpts is like NewReader but takes `Options` as argument, allowing
// callers to indicate if they want to disable md5sum checksum.
func NewReaderWithOpts(ctx context.Context, src io.Reader, opts Options) (*Reader, error) {