hijack_utils.py

import importlib

class CondFunc:
    def __new__(cls, orig_func, sub_func, cond_func):
        self = super(CondFunc, cls).__new__(cls)
        if isinstance(orig_func, str):
            func_path = orig_func.split('.')
            for i in range(len(func_path)-1, -1, -1):
                try:
                    resolved_obj = importlib.import_module('.'.join(func_path[:i]))
                    break
                except ImportError:
                    pass
            for attr_name in func_path[i:-1]:
                resolved_obj = getattr(resolved_obj, attr_name)
            orig_func = getattr(resolved_obj, func_path[-1])
            setattr(resolved_obj, func_path[-1], lambda *args, **kwargs: self(*args, **kwargs))
        self.__init__(orig_func, sub_func, cond_func)
        return lambda *args, **kwargs: self(*args, **kwargs)
    def __init__(self, orig_func, sub_func, cond_func):
        self.__orig_func = orig_func
        self.__sub_func = sub_func
        self.__cond_func = cond_func
    def __call__(self, *args, **kwargs):
        if not self.__cond_func or self.__cond_func(self.__orig_func, *args, **kwargs):
            return self.__sub_func(self.__orig_func, *args, **kwargs)
        else:
            return self.__orig_func(*args, **kwargs)