When some function returns struct, result is wrapped to extra list.

[socketpair]

Suppose this:

...
Method('structMethod', arguments='(si)', returns='(is)')
...
def dbus_structMethod(self, arg):
        print 'swapping and returning swapped struct'
        return (arg[1], arg[0])

When I call it:

res = yield qwe.callRemote('structMethod', ('x', 69))

I expect [69, 'x'] in res, but actually I see [[69, 'x']]