pep8 and import ajustments

* optimzed import statements
* pep8 alignment changes, mostly missing whitespaces, newlines or redundant brackets

prometheus.py

@@ -1,19 +1,16 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-import subprocess
 import logging
-from time import time
-from collections import defaultdict
 from http.server import BaseHTTPRequestHandler, HTTPServer
 from socket import AF_INET6
+from time import time
 from urllib.parse import parse_qs, urlparse
+
 from prometheus_client import (
     CollectorRegistry, Gauge, generate_latest, CONTENT_TYPE_LATEST
 )
 
-
-
 from config import Config
 from metrics import EjabberdMetrics
 
@@ -42,7 +39,8 @@ class DynamicMetricsHandler(BaseHTTPRequestHandler):
                                 {"generator": registry_generator})
         return DynMetricsHandler
 
-class Prometheus():
+
+class Prometheus:
     def __init__(self, metrics):
         self.ttl = 10
         self._last_update = 0
@@ -73,7 +71,7 @@ class Prometheus():
         online_client_ipversion = Gauge('ejabberd_online_client_ipversion', 'count of client software', ["vhost", "node", "client", "ipversion"], registry=registry)
 
         for host in self._metrics.get_vhosts():
-            labels_vhost = (host)
+            labels_vhost = host
 
             registered_vhosts.labels(labels_vhost).set(self._metrics.get_registered(host))
             muc.labels(labels_vhost).set(self._metrics.get_muc(host))