Get group fix,flake8 errors fix,readme and config fix
diff --git a/cvp_checks/tests/test_ntp_sync.py b/cvp_checks/tests/test_ntp_sync.py
index b900e12..09b323f 100644
--- a/cvp_checks/tests/test_ntp_sync.py
+++ b/cvp_checks/tests/test_ntp_sync.py
@@ -17,9 +17,10 @@
         'cmd.run',
         ['date +%s'],
         expr_form='compound')
+    diff = config.get(testname)["time_deviation"] or 30
     for node, time in nodes_time.iteritems():
-        if (int(time) - saltmaster_time) > config.get(testname)["time_deviation"] or \
-                (int(time) - saltmaster_time) < -config.get(testname)["time_deviation"]:
+        if (int(time) - saltmaster_time) > diff or \
+                (int(time) - saltmaster_time) < -diff:
             fail[node] = time
 
     assert not fail, 'SaltMaster time: {}\n' \