diff --git a/Lib/optparse.py b/Lib/optparse.py
index 56b05d6..4a74a68 100644
--- a/Lib/optparse.py
+++ b/Lib/optparse.py
@@ -995,7 +995,7 @@
         """add_option(Option)
            add_option(opt_str, ..., kwarg=val, ...)
         """
-        if type(args[0]) is types.StringType:
+        if type(args[0]) in types.StringTypes:
             option = self.option_class(*args, **kwargs)
         elif len(args) == 1 and not kwargs:
             option = args[0]