Python 中这个 Scratch 块的解决方法是什么功能?

What function could be workaround of this Scratch block in Python?

我想知道,这个 Scratch 块的 workaround/replacement 是什么:

在Python。我知道在JavaScript中答案是:

"..."[... - 1]

代码与JavaScript相同,如:

var alphabet = "ABCDEFGHIJKLNOPQRSTUVWXYZ"
var letter1 = alphabet[0]
var letter2 = alphabet[1]
var letter3 = alphabet[2]
var letter123 = letter1 + letter2 + letter3

alert("The first three letters of the alphabet are: " + letter123)

我很烂**b