str.isidentifier 是有效标识符?

字符串方法 str.isidentifier(),Python 官方文档描述如下:

help(str.isidentifier)
Help on method_descriptor:

isidentifier(self, /)
    Return True if the string is a valid Python identifier, False otherwise.
    
    Call keyword.iskeyword(s) to test whether string s is a reserved identifier,
    such as "def" or "class".

如果字符串是有效的标识符,返回 True,否则返回 False。

''.isidentifier()
False
'1mycode'.isidentifier()
False
'_mycode'.isidentifier()
True
'123'.isidentifier()
False
'_123'.isidentifier()
True
'变量名'.isidentifier()
True
'for'.isidentifier()
True