I tested several ideas in the most popular Python editors: PyCharm, VS Code, Jedi based editors.

By the last [Python Developer Survey](https://www.jetbrains.com/research/python-developers-survey-2018/#development-tools), that covers about 80% of the users.

# EditorConfig helps developers define and maintain consistent
# coding styles between different editors and IDEs
# editorconfig.org

root = true

[*]

indent_style = space
indent_size = 4

end_of_line = lf
charset = utf-8
trim_trailing_whitespace = true
insert_final_newline = true

spelling_languages = en-US

# Markdown files sometimes need trailing whitespaces.
[*.md]
trim_trailing_whitespace = false

There were even some changes to Pydantic itself to support this.

The previous screenshots were taken with [Visual Studio Code](https://code.visualstudio.com).

But you would get the same editor support with [PyCharm](https://www.jetbrains.com/pycharm/) and most of the other Python editors:

<img src="/img/tutorial/body/image05.png">

/// tip

 *
 * <p>Strategies work with domtrip Documents for perfect formatting preservation.
 * Individual strategies can create domtrip Editors from Documents as needed:
 * <pre>
 * Editor editor = new Editor(document);
 * // ... perform domtrip operations ...
 * // Document is automatically updated
 * </pre>
 */
public interface UpgradeStrategy {

    /**

### Application Discovery { #application-discovery }

/// tip

Some editors check for unused function parameters, and show them as errors.

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

By doing that, your editor can provide support even while processing items from the list:

<img src="/img/python-types/image05.png">

Without types, that's almost impossible to achieve.

Notice that the variable `item` is one of the elements in the list `items`.

And still, the editor knows it is a `str`, and provides support for that.

 *
 * <p>This class recursively discovers all POM files in a Maven project hierarchy
 * and loads them as domtrip Documents. Individual strategies can create domtrip Editors
 * from these Documents as needed for superior formatting preservation.
 */
public class PomDiscovery {

    private PomDiscovery() {
        // noop
    }

    /**

 * and reduces code duplication across strategy implementations.
 *
 * <p>Strategies work with domtrip Documents for perfect formatting preservation.
 * Subclasses can create domtrip Editors from Documents as needed:
 * <pre>
 * Editor editor = new Editor(document);
 * // ... perform domtrip operations ...
 * // Document is automatically updated
 * </pre>
 */
public abstract class AbstractUpgradeStrategy implements UpgradeStrategy {

{* ../../docs_src/dependencies/tutorial001_an_py310.py hl[9] *}

But then we get a `dict` in the parameter `commons` of the *path operation function*.

And we know that editors can't provide a lot of support (like completion) for `dict`s, because they can't know their keys and value types.

We can do better...

## What makes a dependency { #what-makes-a-dependency }