diff --git a/pynfe/processamento/serializacao.py b/pynfe/processamento/serializacao.py
index 5f37e5f..e643f1f 100644
--- a/pynfe/processamento/serializacao.py
+++ b/pynfe/processamento/serializacao.py
@@ -438,7 +438,10 @@ class SerializacaoXML(Serializacao):
         # Ex.: NFe35080599999090910270550010000000011518005123
         raiz.attrib['Id'] = nota_fiscal.identificador_unico
 
-        tz = datetime.now().astimezone().strftime('%z')
+        if six.PY2:
+            tz = datetime.now().strftime('%z')
+        else:
+            tz = datetime.now().astimezone().strftime('%z')
         tz = "{}:{}".format(tz[:-2], tz[-2:])
 
         # Dados da Nota Fiscal
diff --git a/pynfe/utils/__init__.py b/pynfe/utils/__init__.py
index 2aeeab6..c82e8eb 100644
--- a/pynfe/utils/__init__.py
+++ b/pynfe/utils/__init__.py
@@ -3,6 +3,7 @@
 import os
 import codecs
 from unicodedata import normalize
+import six
 
 try:
     from lxml import etree
@@ -50,6 +51,9 @@ CARACTERS_ACENTUADOS = {
 
 # @memoize
 def normalizar_municipio(municipio):
+    if six.PY2:
+        return remover_acentos(unicode(municipio.lower())).upper()
+
     if not isinstance(municipio, str):
         municipio = municipio.decode('utf-8')
 
diff --git a/requirements.txt b/requirements.txt
index 1f07a0e..7115abc 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,6 +3,7 @@ pyopenssl
 requests
 lxml
 signxml
+six >= 1.10.0
 
 # Opcional para NFS-e
 #-r requirements-nfse.txt