Check if Rhythmbox is running via Python

I am trying to extract information from Rhythmbox via dbus, but I only want to do so, if Rhythmbox is running. Is there a way to check if Rhythmbox is running via Python without starting it if it is not running?

Whenever I invoke the dbus code like this:

bus = dbus.Bus()
obj = bus.get_object("org.gnome.Rhythmbox", "/org/gnome/Rhythmbox/Shell")
iface = dbus.Interface(obj, "org.gnome.Rhythmbox.Shell)

and Rhythmbox is not running, it then starts it.

Can I check via dbus if Rhythmbox is running without actually starting it? Or is there any other way, other than parsing the list of currently running processes, to do so?

This is similar to Rosh Oxymoron's answer, but arguably neater (albeit untested):

bus = dbus.SessionBus()
if bus.name_has_owner('org.gnome.Rhythmbox'):
    # ...

If you want to be notified when Rhythmbox starts or stops, you can use:

def rhythmbox_owner_changed(new_owner):
    if new_owner == '':
        print 'Rhythmbox is no longer running'
    else:
        print 'Rhythmbox is now running'

bus.watch_name_owner('org.gnome.Rhythmbox')

See the documentation for dbus.bus.BusConnection for more details.