--- a/src/pyams_utils/scripts/zodb.py	Sat Nov 23 01:24:11 2019 +0100
+++ b/src/pyams_utils/scripts/zodb.py	Sat Nov 23 14:57:24 2019 +0100
@@ -10,19 +10,22 @@
 # FOR A PARTICULAR PURPOSE.
 #
 
-__docformat__ = 'restructuredtext'
+"""PyAMS_utils.scripts.zodb module
 
+This module provides a single function which will be used by "pyams_upgrade" command line
+script to upgrade existing database schema when installing a new application release
+"""
 
-# import standard library
 import argparse
 import sys
 import textwrap
 
-# import interfaces
+from pyramid.paster import bootstrap
 
-# import packages
 from pyams_utils.site import site_upgrade
-from pyramid.paster import bootstrap
+
+
+__docformat__ = 'restructuredtext'
 
 
 def upgrade_site():
@@ -38,7 +41,7 @@
 
     config_uri = args.config_uri
     env = bootstrap(config_uri)
-    settings, closer = env['registry'].settings, env['closer']
+    closer = env['closer']
     try:
         site_upgrade(env['request'])
     finally: