'List \'subscribed\' mailbox names in directory matching pattern.
(typ, [data, ...]) = <instance>.lsub(directory=\'""\', pattern=\'*\')
\'data\' are tuples of message part envelope and data.'

def lsub(self, directory='""', pattern='*'):

    name = 'LSUB'
    (typ, dat) = self._simple_command(name, directory, pattern)
    return self._untagged_response(typ, dat, name)
