Use pyupgrade with --py36-plus param.

gns3server/compute/dynamips/dynamips_factory.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 #
 # Copyright (C) 2015 GNS3 Technologies Inc.
 #
@@ -57,11 +56,11 @@ class DynamipsFactory:
 
         if node_type == "dynamips":
             if platform not in PLATFORMS:
-                raise DynamipsError("Unknown router platform: {}".format(platform))
+                raise DynamipsError(f"Unknown router platform: {platform}")
 
             return PLATFORMS[platform](name, node_id, project, manager, dynamips_id, **kwargs)
         else:
             if node_type not in DEVICES:
-                raise DynamipsError("Unknown device type: {}".format(node_type))
+                raise DynamipsError(f"Unknown device type: {node_type}")
 
             return DEVICES[node_type](name, node_id, project, manager, **kwargs)