How to join two sets in one line without using “|”

Question

Assume that S and T are assigned sets. Without using the join operator |, how can I find the union of the two sets? This, for example,

Answer 1

You could use or_ alias:

>>> from operator import or_
>>> from functools import reduce # python3 required
>>> reduce(or_, [{1, 2, 3, 4}, {3, 4, 5, 6}])
set([1, 2, 3, 4, 5, 6])