adding list to set python 3 code example

Example: add list to set python

set.update() or |=

>>> a = set('abc')
>>> l = ['d', 'e']
>>> a.update(l)
>>> a
{'e', 'b', 'c', 'd', 'a'}

>>> l = ['f', 'g']
>>> a |= set(l)
>>> a
{'e', 'b', 'f', 'c', 'd', 'g', 'a'}