Python RestrictedUnpickler issue

We had written code as -

import os
import builtins
import pickle
import sys
sys.tracebacklimit=0
import traceback
import io
from logging import Logger

safe_builtins = {
        'range',
        'complex',
        'set',
        'frozenset'
        }

class RestrictedUnpickler(pickle.Unpickler):
  def find_class(self, module, name):
  # Only allow safe classes from builtins.
   if module == "builtins" and name in safe_builtins:
       return getattr(builtins, name)
    # Forbid everything else.
   raise pickle.UnpicklingError("global '%s.%s' is forbidden" %
   (module, name))

def restricted_loads(s):
    """Helper function analogous to pickle.loads()."""
    return RestrictedUnpickler(io.BytesIO(s)).load()

def func1(a): 
  try: 
    x= restricted_loads(pickle.dumps(a))
    return x 
  except pickle.UnpicklingError : 
    s= pickle.UnpicklingError("unsupported persistent object") 
    return s

def func2(s):
  try:
    x=restricted_loads(pickle.dumps(s))
    return s[x]
  except pickle.UnpicklingError :
    s=traceback.format_exc()
    return s

if __name__ == "__main__":
       a=range(int(input())) 
       b=func1(a)
       print(b)
       y=tuple(input())
       z=func2(y)
       print(z)

Getting TypeError: tuple indices must be integers or slices, not tuple

Input (stdin)

50 
"a", "b", "c", "d", "e", "f", "g", "h"

Your Output (stdout) range(0, 50)

Expected Output

range(0, 50) 
Traceback (most recent call last): 
_pickle.UnpicklingError: global 'builtins.slice' is forbidden

Safe

quatrope / ProperImage

Python RestrictedUnpickler issue #70