Append 'value' to 'key', assuming 'key' is a list.
            If 'key' isn't a list, 'value' will be set as the value of 'key'.

def append_config_item(self, key, value):
        """
            Append 'value' to 'key', assuming 'key' is a list.
            If 'key' isn't a list, 'value' will be set as the value of 'key'.
        """

        return _lxc.Container.set_config_item(self, key, value)