Comment 11 for bug 1008898

(In reply to comment #0)
> Jun 5 08:00:19 ubuntu ubiquity[3109]: dbus.exceptions.DBusException:
> org.freedesktop.DBus.Error.UnknownMethod: Method "AddAndActivateConnection"
> with signature "a{sa{sv}}ss" on interface "(null)" doesn't exist

For D-Bus calls to be reliable, you should specify an interface (use dbus_interface=... in the call, or call the method via a dbus.Interface wrapper). I don't know whether that's what causes this signature mismatch or not, though; it's just best-practice.

When you introspect the object represented by self.manager, what do you get? (To find out, run "gdbus introspect --system -d org.freedesktop.NetworkManager -o /org/freedesktop/NetworkManager -x", assuming self.manager represents the /org/freedesktop/NetworkManager object on org.freedesktop.NetworkManager on the system bus.) I get this, among other things:

...
    <method name="AddAndActivateConnection">
      <arg name="connection" type="a{sa{sv}}" direction="in"/>
      <arg name="device" type="o" direction="in"/>
      <arg name="specific_object" type="o" direction="in"/>
      <arg name="path" type="o" direction="out"/>
      <arg name="active_connection" type="o" direction="out"/>
    </method>
...