RuntimeWarning: non-string key in the __dict__ of class Outputs

[p72dennisxu]

Describe the bug
When importing csp in python 3.13, RuntimeWarning: non-string key in the __dict__ of class Outputs is raised from csp/impl/types/common_definitions.py.

To Reproduce

Install/build csp in python 3.13 and run

import csp

or

from csp.impl.types.common_definitions import Outputs

Expected behavior

No RuntimeWarnings should be raised.

Error Message

Runtime Environment

Additional context

This is coming from python/cpython@f7c05d7 as a resolution for python/cpython#55664