single process running those previous steps *even* if afterwards, you start **multiple processes** (multiple workers) for the application itself. If those steps were run by **multiple processes**, they would **duplicate** the work by running it on **parallel**, and if the steps were something delicate like a database migration, they could cause conflicts with each other.

Of course, there are some cases where there's no problem in running the previous steps multiple times, in that case, it's...

    ```

Jetzt, selbst wenn Sie einen Request mit duplizierten Daten erhalten, werden diese zu einem Set eindeutiger Dinge konvertiert.

Und wann immer Sie diese Daten ausgeben, selbst wenn die Quelle Duplikate hatte, wird es als Set von eindeutigen Dingen ausgegeben.

Und es wird entsprechend annotiert/dokumentiert.

## Verschachtelte Modelle

Jedes Attribut eines Pydantic-Modells hat einen Typ.

### Preprocess the OpenAPI Specification for the Client Generator

The generated code still has some **duplicated information**.

We already know that this method is related to the **items** because that word is in the `ItemsService` (taken from the tag), but we still have the tag name prefixed in the method name too. 😕

    if route.description:
        operation["description"] = route.description
    operation_id = route.operation_id or route.unique_id
    if operation_id in operation_ids:
        message = (
            f"Duplicate Operation ID {operation_id} for function "
            + f"{route.endpoint.__name__}"
        )
        file_name = getattr(route.endpoint, "__globals__", {}).get("__file__")
        if file_name:

And you would also use Alembic for "migrations" (that's its main job).

A "migration" is the set of steps needed whenever you change the structure of your SQLAlchemy models, add a new attribute, etc. to replicate those changes in the database, add a new column, a new table, etc.

And then you can set those same memory limits and requirements in your configurations for your container management system (for example in **Kubernetes**). That way it will be able to **replicate the containers** in the **available machines** taking into account the amount of memory needed by them, and the amount available in the machines in the cluster.