diff --git a/Lib/optparse.py b/Lib/optparse.py
index 4fbe094..5aa3b96 100644
--- a/Lib/optparse.py
+++ b/Lib/optparse.py
@@ -823,11 +823,14 @@
 except NameError:
     (True, False) = (1, 0)
 
-def isbasestring(x):
-    try:
+try:
+    basestring
+except NameError:
+    def isbasestring(x):
+        return isinstance(x, (types.StringType, types.UnicodeType))
+else:
+    def isbasestring(x):
         return isinstance(x, basestring)
-    except:
-        return isinstance(x, types.StringType) or isinstance(x, types.UnicodeType)
 
 
 class Values: