diff --git a/voikko/generate_lex.py b/voikko/generate_lex.py
index f9b337e..1f64da9 100644
--- a/voikko/generate_lex.py
+++ b/voikko/generate_lex.py
@@ -24,7 +24,6 @@ import generate_lex_common
 import voikkoutils
 import xml.dom.minidom
 import codecs
-from string import rfind
 
 flag_attributes = voikkoutils.readFlagAttributes(generate_lex_common.VOCABULARY_DATA + u"/flags.txt")
 
@@ -218,7 +217,7 @@ def handle_word(word):
 	# then all multi part forms must end with a part contained in the single part set.
 	if singlePartForms:
 		for multiPartForm in multiPartForms:
-			lastPart = multiPartForm[max(rfind(multiPartForm, u"="), rfind(multiPartForm, u"|"), rfind(multiPartForm, u"-")) + 1:]
+			lastPart = multiPartForm[max(multiPartForm.rfind(u"="), multiPartForm.rfind(u"|"), multiPartForm.rfind(u"-")) + 1:]
 			if lastPart not in singlePartForms:
 				sys.stderr.write(u"ERROR: suspicious alternative spelling: %s\n" % multiPartForm)
 				sys.exit(1)