'Retrieves LUNs with specified args.'

def get_lun_by_args(self, **args):

    lun_info = netapp_api.NaElement.create_node_with_children('lun-list-info', **args)
    result = self.connection.invoke_successfully(lun_info, True)
    luns = result.get_child_by_name('luns')
    return luns.get_children()
