diff --git a/pynfe/utils/bar_code_128.py b/pynfe/utils/bar_code_128.py
index e5d0cae..f3def0a 100644
--- a/pynfe/utils/bar_code_128.py
+++ b/pynfe/utils/bar_code_128.py
@@ -162,6 +162,7 @@ class Code128:
       current_charset = None
       pos=sum=0
       skip=False
+      strCode=""
       for c in range(len(code)):
           if skip:
               skip=False