diff --git a/lib/wind/gen-errorlist.py b/lib/wind/gen-errorlist.py
index f0b952478..bf70ddff0 100644
--- a/lib/wind/gen-errorlist.py
+++ b/lib/wind/gen-errorlist.py
@@ -50,7 +50,7 @@ if len(sys.argv) != 3:
 tables = rfc3454.read(sys.argv[1])
 t2 = rfc4518.read()
 
-for x in t2.iterkeys():
+for x in t2.keys():
     tables[x] = t2[x]
 
 error_list = stringprep.get_errorlist()