all: changes from python 2 syntax to python3 and removing dead code

There were python 2 methods that are not used anymore so now
it's in python 3. Added helper fuctions so that the code is more clear

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/540

examples/python/dbus/nm-state.py

@@ -68,7 +68,6 @@ for d in devices:
     else:
         print("Device %s is not activated (state=%s)" % (name, device_states[state]))
 
-
 # Get active connection state
 manager_prop_iface = dbus.Interface(proxy, "org.freedesktop.DBus.Properties")
 active = manager_prop_iface.Get("org.freedesktop.NetworkManager", "ActiveConnections")
@@ -90,4 +89,4 @@ for a in active:
     con_details = con_iface.GetSettings()
     con_name = con_details["connection"]["id"]
 
-    print("Connection '%s' is %s" % (con_name, connectivity_states[state].lower()))
+    print("Connection '%s' is %s" % (con_name, connectivity_states[state]))