HOT-FIX: NoneType exception em LexML

sapl/lexml/OAIServer.py

@@ -237,6 +237,7 @@ class OAIServer:
             return None
 
     def oai_query(self, offset=0, batch_size=10, from_=None, until=None, identifier=None):
+        if from_:
             from_ = timezone.make_aware(from_)  # convert from naive to timezone aware datetime
         esfera = self.get_esfera_federacao()
         offset = 0 if offset < 0 else offset