[PYTHON] List types not handled correctly

Description

List types in the Python generated models are not handled correctly. Please see details below.

Swagger-codegen version

swagger-codegen-cli 3.0.23

Swagger declaration file content or url

openapi: 3.0.0
paths:
  /pets:
    get:
      tags:
        - pet
      summary: Get pets
      operationId: getPets
      responses:
        '200':
          description: Successful operation
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Pets'
components:
  schemas:
    Pet:
      type: object
      properties:
        name:
          type: string
          description: 'Pet name'
    Pets:
      type: array
      items:
        $ref: '#/components/schemas/Pet'

Command line used for generation

java -jar swagger-codegen-cli-3.0.23.jar generate -i model.yaml -l python -o python_client

Steps to reproduce

java -jar swagger-codegen-cli-3.0.23.jar generate -i model.yaml -l python -o python_client
Notice:

    attribute_map = {
    }

in python_client/swagger_client/models/pets.py.

However the java client seems to work:
java -jar swagger-codegen-cli-3.0.23.jar generate -i model.yaml -l java -o java_client

public class Pets extends ArrayList<Pet> {

in java_client/src/main/java/io/swagger/client/model/Pets.java.

Related issues/PRs

https://github.com/swagger-api/swagger-codegen/issues/9664. I do not agree with the conclusion drawn in that issue, the spec is valid and the java generator handles it correctly. Following the suggested solution of wrapping the array in an object will break existing clients and introduce unnecessary complexity in the spec.

Suggest a fix/enhancement

Start by reproducing the issue with the provided OpenAPI YAML and Python generation command, then inspect python_client/swagger_client/models/pets.py and compare it with the Java output. Trace how the Python generator handles the array schema and verify that the generated list model represents its Pet items correctly.