add to set in pyhtron code example

Example: sets in python

set_of_base10_numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 0}
set_of_base2_numbers = {1, 0}

intersection = set_of_base10_numbers.intersection(set_of_base2_numbers)
union = set_of_base10_numbers.union(set_of_base2_numbers)

'''
intersection: {0, 1}:
	if the number is contained in both sets it becomes part of the intersection
union: {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}:
	if the number exists in at lease one of the sets it becomes part of the union
'''