关键字参数必须跟随在位置参数后面! 因为python函数在解析参数时, 是按照顺序来的, 位置参数是必须先满足, 才能考虑其他可变参数.，否则报错如下：

In [74]: print(s1.format(name='jenkins',"good","kg",a='python'))

File "", line 1

print(s1.format(name='jenkins',"good","kg",a='python'))

^

SyntaxError: positional argument follows keyword argument

场景：

In [79]: s1=('{name} is {}, he is 100{}, he love is {a}')

错误做法：

In [76]: print(s1.format(name='jenkins',a='python','good','kg'))

File "", line 1

print(s1.format(name='jenkins',a='python','good','kg'))

^

SyntaxError: positional argument follows keyword argument

正确做法：

In [78]: print(s1.format("good","kg",a='python',name='jenins'))

jenins is good, he is 100kg, he love is python

意思就是说先写关键字，关键字写完之后，再写赋值，赋值跟在关键字之后