autodoc-automodule-decorated-docstrings.py

from functools import update_wrapper

class Operation:
     @classmethod
     def register(cls, code):
         """Registration"""
         def inner(func):
             result = cls(func, code)
             update_wrapper(result, func)
             return result
         return inner
     def __init__(self, func, code):
         # …
         print('initializing ' + func.__name__ + ' ' + code)

@Operation.register('foo')
def func(arg):
     """Documentation of decorated function"""
     pass