exec code safely on python

exec.py

import sys
from contextlib import closing
from StringIO import StringIO

def run(code):
  with closing(StringIO()) as sout, closing(StringIO()) as serr:
    sys.stdout = sout
    sys.stderr = serr
    
    exec code in {'__builtins__': {}}, {}
    sys.stdout = sys.__stdout__
    sys.stderr = sys.__stderr__
    
    return sout.getvalue(), serr.getvalue()