Compatibility issue with Python 3.9

[hirak-saharia]

TypeError: unsupported operand type(s) for |: 'type' and 'NoneType'

Enhance code that runs smoothly on both Python 3.9 and 3.10+ to the following get_schema definition:

• def get_schema(conf: dict | None = None) -> dict:

[pikhovkin]

See supported versions
Or welcome to PR