Enable black in tox.ini

Change-Id: Icd3d56e7b2eb871ce8d4ef60fbf079ac59b1f117
Signed-off-by: garciadeblas <gerardo.garciadeblas@telefonica.com>
diff --git a/osm_pla/cmd/pla_server.py b/osm_pla/cmd/pla_server.py
index 767e61d..409f14d 100755
--- a/osm_pla/cmd/pla_server.py
+++ b/osm_pla/cmd/pla_server.py
@@ -24,16 +24,18 @@
 
 
 def main():
-    parser = argparse.ArgumentParser(prog='osm-policy-agent')
-    parser.add_argument('--config-file', nargs='?', help='PLA configuration file')
+    parser = argparse.ArgumentParser(prog="osm-policy-agent")
+    parser.add_argument("--config-file", nargs="?", help="PLA configuration file")
     args = parser.parse_args()
     cfg = Config(args.config_file)
 
     root = logging.getLogger()
-    root.setLevel(logging.getLevelName(cfg.get('global', 'loglevel')))
+    root.setLevel(logging.getLevelName(cfg.get("global", "loglevel")))
     ch = logging.StreamHandler(sys.stdout)
-    ch.setLevel(logging.getLevelName(cfg.get('global', 'loglevel')))
-    formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s', '%m/%d/%Y %I:%M:%S %p')
+    ch.setLevel(logging.getLevelName(cfg.get("global", "loglevel")))
+    formatter = logging.Formatter(
+        "%(asctime)s - %(name)s - %(levelname)s - %(message)s", "%m/%d/%Y %I:%M:%S %p"
+    )
     ch.setFormatter(formatter)
     root.addHandler(ch)
 
@@ -45,5 +47,5 @@
     server.run()
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()