Just functions that look the same as the *path operation functions*.

But still, it is very powerful, and allows you to declare arbitrarily deeply nested dependency "graphs" (trees).

/// tip

All this might not seem as useful with these simple examples.

But you will see how useful it is in the chapters about **security**.

And you will also see the amounts of code it will save you.

They will be added to the OpenAPI schema and used by the automatic documentation interfaces:

<img src="/img/tutorial/path-operation-configuration/image01.png">

### Tags with Enums

If you have a big application, you might end up accumulating **several tags**, and you would want to make sure you always use the **same tag** for related *path operations*.

In these cases, it could make sense to store the tags in an `Enum`.

///

## Forbid Extra Cookies

In some special use cases (probably not very common), you might want to **restrict** the cookies that you want to receive.

import java.lang.reflect.Method;
import junit.framework.TestCase;

/**
 * Tests that all package-private {@code writeReplace} methods are overridden in any existing
 * subclasses. Without such overrides, optimizers might put a {@code writeReplace}-containing class
 * and its subclass in different packages, causing the serialization system to fail to invoke {@code

 *       where the {@code ...} contains the names of all the other {@code ParametricNullness}
 *       annotations in Guava. Or you might prefer to omit Guava from your {@code AnnotatedPackages}
 *       list.
 *   <li><a href="https://developers.google.com/j2objc">J2ObjC</a>

 *       where the {@code ...} contains the names of all the other {@code ParametricNullness}
 *       annotations in Guava. Or you might prefer to omit Guava from your {@code AnnotatedPackages}
 *       list.
 *   <li><a href="https://developers.google.com/j2objc">J2ObjC</a>

  // http://docs.oracle.com/javase/6/docs/technotes/guides/security/crypto/CryptoSpec.html
  //  - Some providers may choose to also include alias names.
  //  - For example, the "SHA-1" algorithm might be referred to as "SHA1".
  //  - The algorithm name is not case-sensitive.
  private static final ImmutableMap<String, HashFunction> ALGORITHMS =
      new ImmutableMap.Builder<String, HashFunction>()

import jcifs.smb1.util.Base64;

/**
 * This class is used internally by <tt>NtlmHttpFilter</tt>,
 * <tt>NtlmServlet</tt>, and <tt>NetworkExplorer</tt> to negiotiate password
 * hashes via NTLM SSP with MSIE. It might also be used directly by servlet
 * containers to incorporate similar functionality.
 * <p>
 * How NTLMSSP is used in conjunction with HTTP and MSIE clients is

- Select a Adoptium Java 17 VM as "Gradle JVM"
- Revert the Git changes to files in the `.idea` folder

NOTE: Due to the project size, the very first import can take a while and IntelliJ might become unresponsive for several seconds during this period.

For example, if you want to read or manipulate the request body before it is processed by your application.

/// danger

This is an "advanced" feature.

If you are just starting with **FastAPI** you might want to skip this section.

///

## Use cases

Some use cases include: