[Python] Inheritance doesn't work

Created by: emreakca

Description

The generated Python SubClass doesn't inherited from the BaseClass, when allOf is used.

SubClass:
  allOf:
    - $ref: '#/components/schemas/BaseClass'

The generated class shows

class SubClass(object):

instead of

class SubClass(BaseClass):

This issue was already posted (#453 (closed)), but it's not solved nor answered.

openapi-generator version

3.1.1

Command line used for generation

java -jar ~/openapi-generator-cli-3.1.1.jar generate -g python -i openapi.json -o generated/python-client

Suggestion

Either do the inheritance correctly (as shown at the beginning), with the right constructors (__init__) or add the Properties of the BaseClass to the SubClass, as in swagger 2.