*   <li><strong>Duplicate Dependencies</strong>: Removes duplicate dependency declarations that Maven 4 strictly validates</li>
 *   <li><strong>Duplicate Plugins</strong>: Removes duplicate plugin declarations that Maven 4 strictly validates</li>
 *   <li><strong>Unsupported Repository Expressions</strong>: Comments out repositories with expressions not supported by Maven 4</li>

You can use the same type declarations with `str`, `float`, `bool` and many other complex data types.

Several of these are explored in the next chapters of the tutorial.

## Order matters { #order-matters }

But you can re-order them, and have the value without a default (the query parameter `q`) first.

It doesn't matter for **FastAPI**. It will detect the parameters by their names, types and default declarations (`Query`, `Path`, etc), it doesn't care about the order.

So, you can declare your function as:

{* ../../docs_src/path_params_numeric_validations/tutorial002_py39.py hl[7] *}

pass the internal type(s) as "type parameters" using square brackets: `[` and `]`

```Python
my_list: list[str]
```

That's all standard Python syntax for type declarations.

Use that same standard syntax for model attributes with internal types.

So, in our example, we can make `tags` be specifically a "list of strings":

   */

  @Override
  public Object[] toArray() {
    return snapshotElementsToList().toArray();
  }

  @Override
  @SuppressWarnings("nullness") // b/192354773 in our checker affects toArray declarations
  public <T extends @Nullable Object> T[] toArray(T[] array) {
    return snapshotElementsToList().toArray(array);
  }

  /*
   * We'd love to use 'new ArrayList(this)' or 'list.addAll(this)', but

    "unitTests": false,
    "functionalTests": true,
    "crossVersionTests": false
  },
  {
    "name": "instrumentation-declarations",
    "path": "platforms/core-runtime/instrumentation-declarations",
    "unitTests": false,
    "functionalTests": false,
    "crossVersionTests": false
  },
  {
    "name": "instrumentation-reporting",

We could do better.

We can declare a `UserBase` model that serves as a base for our other models. And then we can make subclasses of that model that inherit its attributes (type declarations, validation, etc).

All the data conversion, validation, documentation, etc. will still work as normally.

of the last non-empty expression list.
</p>


<h3 id="Type_declarations">Type declarations</h3>

<p>
A type declaration binds an identifier, the <i>type name</i>, to a <a href="#Types">type</a>.
Type declarations come in two forms: alias declarations and type definitions.
</p>

<pre class="ebnf">
TypeDecl = "type" ( TypeSpec | "(" { TypeSpec ";" } ")" ) .

**FastAPI** takes advantage of these type hints to do several things.

With **FastAPI** you declare parameters with type hints and you get:

* **Editor support**.
* **Type checks**.

...and **FastAPI** uses the same declarations to:

* **Define requirements**: from request path parameters, query parameters, headers, bodies, dependencies, etc.
* **Convert data**: from the request to the required type.
* **Validate data**: coming from each request:

            <option value="$PROJECT_DIR$/platforms/core-runtime/instrumentation-agent-services" />
            <option value="$PROJECT_DIR$/platforms/core-runtime/instrumentation-declarations" />
            <option value="$PROJECT_DIR$/platforms/core-runtime/instrumentation-reporting" />
            <option value="$PROJECT_DIR$/platforms/core-runtime/internal-instrumentation-api" />