One more attempt at nerfing sys

restrictedpython_code_eval.py

@@ -21,6 +21,7 @@ import copy
 import faulthandler
 import itertools
 import importlib
+import importlib.util
 import io
 import multiprocessing
 import os
@@ -407,7 +408,10 @@ ALLOWED_SYS_NAMES = ['maxsize']
 class AllowListImporter:
     def __init__(self, allowed_imports: List[str]):
         self.allowed_imports = allowed_imports
-        inner_sys = copy.deepcopy(importlib.__import__('sys'))
+        sys_spec = importlib.util.find_spec('sys')
+        inner_sys = importlib.util.module_from_spec(sys_spec)  # type: ignore
+        sys_spec.loader.exec_module(inner_sys)  # type: ignore
+
         for key in list(dir(inner_sys)):
             if key not in ALLOWED_SYS_NAMES:
                 delattr(inner_sys, key)