Fix MyPy Errors for Qubole provider.

[kazanzhy]

Fix MyPy Errors for Qubole provider.

related: #19891

[kazanzhy]

One test is failed, but it is tests/providers/docker/decorators/test_docker.py::TestDockerDecorator::test_basic_docker_operator:.
Seems it is not related to Qubole

[potiuk]

I found a better? way of handling it. I think it's a bit nicer:

def execute(self: BaseOperator, context=None) -> None:  # type: ignore[misc]

It's not as spectacular as in my case where I got rid of 5 self.* references this way, but I think it is more explicit (the ignore above has to be added silence another MyPy error "BaseOperator is not a superclass of Mixin'

https://github.com/apache/airflow/pull/20329/files#r770023071

[kazanzhy]

Nice solution :)
It is very similar to using Protocol but without protocol. Unfortunately, it doesn't work for me.
In this case, BaseOperator hasn't method get_hook as well as none of the super classes have execute method.

I think might be cases where some class inherits from mixin and two other classes and these classes have such different attributes and can't be reduced to one. But it will be another story.
Thanks for the suggestion

[potiuk]

Indeed - some instability of external APIs used for tests (have a number of those in my case) - but I think it would be nice to fix the Mixin problem in the way I found :)

[kazanzhy]

So I see that mypy avoids using Mixins, which with the absence of Interfaces in Python, leads to very complex inheritance or code repetition. Am I right?