Using these `dependencies` in the *path operation decorator* you can make sure they are executed while avoiding editor/tooling errors.

It might also help avoid confusion for new developers that see an unused parameter in your code and could think it's unnecessary.

///

/// info

In this example we use invented custom headers `X-Key` and `X-Token`.

        // If the implementation uses identityHashCode(), referential equality is
        // probably intended. So no point in using an equal-but-different factory argument.
        // We check twice to avoid confusion caused by accidental hash collision.
        equalArgs.set(i, shouldBeEqualArg);
      }
    }
    return equalArgs;
  }

  private static boolean hashCodeInsensitiveToArgReference(

*   Fixes crashes stemming from incomplete validation in signal ops ([CVE-2022-29213](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-29213))
*   Fixes a type confusion leading to `CHECK`-failure based denial of service ([CVE-2022-29209](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-29209))

        // If the implementation uses identityHashCode(), referential equality is
        // probably intended. So no point in using an equal-but-different factory argument.
        // We check twice to avoid confusion caused by accidental hash collision.
        equalArgs.set(i, shouldBeEqualArg);
      }
    }
    return equalArgs;
  }

  private static boolean hashCodeInsensitiveToArgReference(

 * {@link Multimap} itself). Prefer subtypes such as {@link ImmutableSetMultimap} or {@link
 * ImmutableListMultimap}, which have well-defined {@link #equals} semantics, thus avoiding a common
 * source of bugs and confusion.
 *
 * <p><b>Note:</b> every {@link ImmutableMultimap} offers an {@link #inverse} view, so there is no
 * need for a distinct {@code ImmutableBiMultimap} type.
 *
 * <p><a id="iteration"></a>
 *

on:
  workflow_run:
    workflows: [Test]
    types: [completed]

permissions:
  statuses: write

env:
  UV_SYSTEM_PYTHON: 1

jobs:
  smokeshow:
    if: ${{ github.event.workflow_run.conclusion == 'success' }}
    runs-on: ubuntu-latest

    steps:
      - name: Dump GitHub context
        env:
          GITHUB_CONTEXT: ${{ toJson(github) }}
        run: echo "$GITHUB_CONTEXT"

```console
$ C:\opt\custompython\bin\python
```

</div>

////

This information will be useful when learning about [Virtual Environments](virtual-environments.md){.internal-link target=_blank}.

## Conclusion { #conclusion }

With this you should have a basic understanding of what **environment variables** are and how to use them in Python.

And you have to wait 🕙 in the line for a long time or you lose your turn.

You probably wouldn't want to take your crush 😍 with you to run errands at the bank 🏦.

### Burger Conclusion { #burger-conclusion }

In this scenario of "fast food burgers with your crush", as there is a lot of waiting 🕙, it makes a lot more sense to have a concurrent system ⏸🔀⏯.

This is the case for most of the web applications.

The same example would then look like:

{* ../../docs_src/dependencies/tutorial004_an_py310.py hl[19] *}

...and **FastAPI** will know what to do.

/// tip

If that seems more confusing than helpful, disregard it, you don't *need* it.

It is just a shortcut. Because **FastAPI** cares about helping you minimize code repetition.

* And many other things

## Conclusion { #conclusion }

If you read and understood all this, now **you know much more** about virtual environments than many developers out there. 🤓