import dbus

bus = dbus.SessionBus()
proxy = bus.get_object("testing.Object", "/testing/Object")
iface = dbus.Interface(proxy, "testing.Object")

iface.TestMethod([['a', 'b'], ['c', 'd']])

# for this signature...
# <method name="TestMethod">
#  <arg type="aas" name="ids" direction="in" />
#  <arg type="aas" name="values" direction="out" />
# </method>

# ...never even gets on the bus, but fails with:
# Traceback (most recent call last):
#   File "<stdin>", line 1, in ?
#   File "/var/lib/python-support/python2.4/dbus/proxies.py", line 90, in __call__
#     iter.append_strict(arg, sig)
#   File "dbus_bindings.pyx", line 1043, in dbus_bindings.MessageIter.append_strict
#   File "dbus_bindings.pyx", line 1313, in dbus_bindings.MessageIter.append_array
#   File "dbus_bindings.pyx", line 1009, in dbus_bindings.MessageIter.append_strict
#   File "dbus_bindings.pyx", line 1176, in dbus_bindings.MessageIter.append_string
# AttributeError: 'list' object has no attribute 'encode'