'Item({!r})'.format(self.name) 中的 !r 是什么意思

[patrickstar]

Python Cookbook 3rd 的 1.5 章有一段代码如下：

>>> class Item:
...     def __init__(self,name):
...             self.name=name
...     def __repr__(self):
...             return 'Item({!r})'.format(self.name)
...

请问 return 语句中的 !r 是什么意思，我咋个都搜不到，谢谢！

[wd]

Three conversion flags are currently supported: '!s' which calls str() on the value, '!r' which calls repr() and '!a' which calls ascii().

[patrickstar]

@wd thanks