diff --git a/tatu/api/models.py b/tatu/api/models.py
index 0809e30..beba558 100644
--- a/tatu/api/models.py
+++ b/tatu/api/models.py
@@ -104,7 +104,7 @@ class Authority(object):
 class UserCerts(object):
     @falcon.before(validate)
     def on_post(self, req, resp):
-        # TODO: validation
+        # TODO(pino): validation
         try:
             user = db.createUserCert(
                 self.session,
diff --git a/tatu/db/models.py b/tatu/db/models.py
index 89be1f2..06feeee 100644
--- a/tatu/db/models.py
+++ b/tatu/db/models.py
@@ -11,11 +11,9 @@
 #    under the License.
 
 import falcon
-import os
 import sqlalchemy as sa
 import sshpubkeys
-import uuid
-from Crypto.PublicKey import RSA
+    from Crypto.PublicKey import RSA
 from datetime import datetime
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.declarative import declarative_base
@@ -125,7 +123,7 @@ def createToken(session, host_id, auth_id, hostname):
         token = session.query(Token).filter(Token.host_id == host_id).one()
         if token is not None:
             return token
-    except:
+    except Exception:
         pass
 
     token = Token(host_id=host_id,
@@ -164,12 +162,12 @@ def createHostCert(session, token_id, host_id, pub):
     if token.used:
         if token.fingerprint_used != fingerprint:
             raise falcon.HTTPConflict(
-                description='The token was previously used with a different public key')
+                description='Token already signed a different public key')
         # The token was already used for same host and pub key. Return record.
         host = session.query(HostCert).get([host_id, fingerprint])
         if host is None:
             raise falcon.HTTPInternalServerError(
-                description='The token was used, but no corresponding Host record was found.')
+                description='Token already used, but Host record not found.')
         if host.token_id == token_id:
             return host
         raise falcon.HTTPConflict(
diff --git a/tatu/db/persistence.py b/tatu/db/persistence.py
index 861bf90..248c128 100644
--- a/tatu/db/persistence.py
+++ b/tatu/db/persistence.py
@@ -22,7 +22,7 @@ def get_url():
     # return os.getenv("DATABASE_URL", "sqlite:///:memory:")
 
 
-class SQLAlchemySessionManager:
+class SQLAlchemySessionManager(object):
     """
     Create scoped session for every request and close it when the request ends
     """
diff --git a/tatu/ftests/test_api.py b/tatu/ftests/test_api.py
index d5184bd..01a4722 100644
--- a/tatu/ftests/test_api.py
+++ b/tatu/ftests/test_api.py
@@ -11,7 +11,6 @@
 #    under the License.
 
 import json
-import os
 import requests
 import sshpubkeys
 import uuid
diff --git a/tatu/notifications.py b/tatu/notifications.py
index 9d889da..68cf564 100644
--- a/tatu/notifications.py
+++ b/tatu/notifications.py
@@ -18,7 +18,7 @@ from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_serialization import jsonutils
 from sqlalchemy import create_engine
-from sqlalchemy.orm import sessionmaker, scoped_session
+from sqlalchemy.orm import scoped_session, sessionmaker
 
 from tatu.db.models import createAuthority
 from tatu.db.persistence import get_url
@@ -64,9 +64,9 @@ class NotificationEndpoint(object):
 
 def main():
     logging.register_options(CONF)
-    extra_log_level_defaults = ['tatu=DEBUG', '__main__=DEBUG']
-    logging.set_defaults(default_log_levels=logging.get_default_log_levels() +
-                                            extra_log_level_defaults)
+    log_levels = logging.get_default_log_levels() + \
+                 ['tatu=DEBUG', '__main__=DEBUG']
+    logging.set_defaults(default_log_levels=log_levels)
     logging.setup(CONF, DOMAIN)
 
     transport = oslo_messaging.get_notification_transport(CONF)
diff --git a/tatu/utils.py b/tatu/utils.py
index e5c1d9a..4161178 100644
--- a/tatu/utils.py
+++ b/tatu/utils.py
@@ -46,14 +46,14 @@ def generateCert(auth_key, entity_key, hostname=None, principals='root'):
         cert = ''
         with open(cert_file, 'r') as text_file:
             cert = text_file.read()
-    except Exception as e:
-        print e
+    #except Exception as e:
+    #    print e
     finally:
         # Delete temporary files
         for file in [ca_file, pub_file, cert_file]:
             try:
                 os.remove(file)
                 pass
-            except:
+            except Exception:
                 pass
         return cert