diff --git a/Stemmer.py b/Stemmer.py
index 5094bd4..eb7dd2e 100644
--- a/Stemmer.py
+++ b/Stemmer.py
@@ -335,7 +335,7 @@ def stemWords(self, words):
     def _stem(cls, word):
         was_unicode = False
 
-        if isinstance(word, unicode):
+        if isinstance(word, bytes):
             was_unicode = True
             try:
                 word = word.encode('ascii')