## `Security()`

For many scenarios, you can handle security (authorization, authentication, etc.) with dependencies, using `Depends()`.

But when you want to also declare OAuth2 scopes, you can use `Security()` instead of `Depends()`.

You can import `Security()` directly from `fastapi`:

```python
from fastapi import Security
```

/// tip

If you want to **learn FastAPI** in a structured way (recommended), go and read the [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank} chapter by chapter instead.

import java.util.List;

import org.apache.maven.settings.Settings;

/**
 * Collects the output of the settings builder.
 *
 * @deprecated since 4.0.0, use {@link org.apache.maven.api.services.SettingsBuilder} instead
 */
@Deprecated(since = "4.0.0")
class DefaultSettingsBuildingResult implements SettingsBuildingResult {

    private Settings effectiveSettings;

    private List<SettingsProblem> problems;

/**
 * Builds the effective settings from a user settings file, a project settings file
 * and/or a global settings file.
 *
 * @deprecated since 4.0.0, use {@link org.apache.maven.api.services.SettingsBuilder} instead
 */
@Deprecated(since = "4.0.0")
public interface SettingsBuilder {

    /**
     * Builds the effective settings of the specified settings files.
     *

   *
   * @throws IllegalArgumentException if the given value is already bound to a different key in this
   *     bimap. The bimap will remain unmodified in this event. To avoid this exception, call {@link
   *     #forcePut} instead.
   */
  @CanIgnoreReturnValue
  @Override
  @CheckForNull
  V put(@ParametricNullness K key, @ParametricNullness V value);

  /**

 * provided {@code standardOffer} method.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code
 * default} methods. Instead, it inherits their default implementations. When those implementations
 * invoke methods, they invoke methods on the {@code ForwardingBlockingDeque}.
 *

 * an expressive source hint for the model problem. Instead, the source hint is configured by the model builder before
 * it delegates to other components that potentially encounter problems. Then, the problem reporter can focus on
 * providing a simple error message, leaving the donkey work of creating a nice model problem to this component.
 *
 * @deprecated use {@link org.apache.maven.api.services.ModelBuilder} instead
 */
@Deprecated(since = "4.0.0")

## HTTPX

Even if your **FastAPI** application uses normal `def` functions instead of `async def`, it is still an `async` application underneath.

#### `lru_cache` Technical Details

`@lru_cache` modifies the function it decorates to return the same value that was returned the first time, instead of computing it again, executing the code of the function every time.

                automatically cancel the request and send the client an error.

                If `auto_error` is set to `False`, when the query parameter is not
                available, instead of erroring out, the dependency result will be
                `None`.

                This is useful when you want to have optional authentication.