diff --git a/osm_mon/collector/vnf_collectors/openstack.py b/osm_mon/collector/vnf_collectors/openstack.py
index da98cc6..2005ebe 100644
--- a/osm_mon/collector/vnf_collectors/openstack.py
+++ b/osm_mon/collector/vnf_collectors/openstack.py
@@ -123,13 +123,13 @@
                     except ValueError:
                         log.warning(
                             "Could not find resource_uuid for vdur %s, vnf_member_index %s, nsr_id %s. "
-                            "Was it recently deleted?".format(
-                                vdur['name'], vnf_member_index, nsr_id))
+                            "Was it recently deleted?",
+                            vdur['name'], vnf_member_index, nsr_id)
                         continue
                     if self.backend == 'ceilometer':
                         measures = self.client.samples.list(meter_name=openstack_metric_name, limit=1, q=[
                             {'field': 'resource_id', 'op': 'eq', 'value': resource_id}])
-                        if len(measures):
+                        if measures:
                             metric = VnfMetric(nsr_id, vnf_member_index, vdur['name'], metric_name,
                                                measures[0].counter_volume)
                             metrics.append(metric)
@@ -146,7 +146,7 @@
                                                                                start=start_date,
                                                                                resource_id=interface['id'],
                                                                                granularity=self.granularity)
-                                    if len(measures):
+                                    if measures:
                                         total_measure += measures[-1][2]
 
                                 except gnocchiclient.exceptions.NotFound as e:
@@ -161,7 +161,7 @@
                                                                            start=start_date,
                                                                            resource_id=resource_id,
                                                                            granularity=self.granularity)
-                                if len(measures):
+                                if measures:
                                     metric = VnfMetric(nsr_id, vnf_member_index, vdur['name'], metric_name,
                                                        measures[-1][2])
                                     metrics.append(metric)
diff --git a/osm_mon/collector/vnf_collectors/vio.py b/osm_mon/collector/vnf_collectors/vio.py
index 8e43878..5bcf66e 100644
--- a/osm_mon/collector/vnf_collectors/vio.py
+++ b/osm_mon/collector/vnf_collectors/vio.py
@@ -65,8 +65,8 @@
 class VIOCollector(BaseVimCollector):
     def __init__(self, config: Config, vim_account_id: str):
         super().__init__(config, vim_account_id)
-        self.common_db = CommonDbClient()
-        self.auth_manager = AuthManager()
+        self.common_db = CommonDbClient(config)
+        self.auth_manager = AuthManager(config)
         vim_account_info = self.auth_manager.get_credentials(vim_account_id)
         cfg = json.loads(vim_account_info.config)
         self.vrops_site = cfg['vrops_site']
diff --git a/osm_mon/collector/vnf_collectors/vmware.py b/osm_mon/collector/vnf_collectors/vmware.py
index ba499c7..557fa38 100644
--- a/osm_mon/collector/vnf_collectors/vmware.py
+++ b/osm_mon/collector/vnf_collectors/vmware.py
@@ -62,9 +62,6 @@
     "packets_sent": "net:Aggregate of all instances|packetsTxPerSec",
 }
 
-# Disable warnings from self-signed certificates.
-requests.packages.urllib3.disable_warnings()
-
 
 class VMwareCollector(BaseVimCollector):
     def __init__(self, config: Config, vim_account_id: str):
diff --git a/osm_mon/evaluator/evaluator.py b/osm_mon/evaluator/evaluator.py
index 90c0c17..24e8e43 100644
--- a/osm_mon/evaluator/evaluator.py
+++ b/osm_mon/evaluator/evaluator.py
@@ -77,7 +77,7 @@
             json_response = r.json()
             if json_response['status'] == 'success':
                 result = json_response['data']['result']
-                if len(result):
+                if result:
                     metric_value = float(result[0]['value'][1])
                     log.info("Metric value: %s", metric_value)
                     if alarm.operation.upper() == 'GT':