diff --git a/mongo/mongocwarler.py b/mongo/mongocwarler.py
index d10808f..43ec1d5 100644
--- a/mongo/mongocwarler.py
+++ b/mongo/mongocwarler.py
@@ -52,7 +52,7 @@ def calculate_checksums(text):
     for c in text:
         cv = ord(c)
         sz += 1
-        if cv > 64:
+        if cv > 64:  # ignore non-ascii
             hval += (hval << 3) + cv
             zv = hval >> 31
             hval &= 0x7fffffff