Why can't I add a tuple to a list with the '+' operator in Python?

Question

Python not support adding a tuple to a list:

>>> [1,2,3] + (4,5,6)
Traceback (most recent call last):
  File \"\", line 1, in 

        

Answer 1

This is not supported because the + operator is supposed to be symmetric. What return type would you expect? The Python Zen includes the rule

In the face of ambiguity, refuse the temptation to guess.

The following works, though:

a = [1, 2, 3]
a += (4, 5, 6)

There is no ambiguity what type to use here.