code: def _handle_ls(self):
          
          try:
              arg1 = self.argument(1)
              arg2 = self.argument(2)
  
              todos = []
              if arg2 == 'to' or arg1 == 'before':
                  # dep ls 1 to OR dep ls before 1
                  number = arg1 if arg2 == 'to' else arg2
                  todo = self.todolist.todo(number)
                  todos = self.todolist.children(todo)
              elif arg1 in {'to', 'after'}:
                  # dep ls to 1 OR dep ls after 1
                  number = arg2
                  todo = self.todolist.todo(number)
                  todos = self.todolist.parents(todo)
              else:
                  raise InvalidCommandArgument
  
              sorter = Sorter(config().sort_string())
              instance_filter = Filter.InstanceFilter(todos)
              view = View(sorter, [instance_filter], self.todolist)
              self.out(self.printer.print_list(view.todos))
          except InvalidTodoException:
              self.error("Invalid todo number given.")
          except InvalidCommandArgument:
              self.error(self.usage())
docs: Handles the ls subsubcommand.