s = set()
print('s = {}'.format(s))
evens = {i for i in range(10) if i % 2 == 0}
print('evens = {}'.format(evens))
s.add(8)
print('s = {}'.format(s))
cardinality = len(s)
print('cardinality = {}'.format(cardinality))
has_one = 1 in s
print('has_one = {}'.format(has_one))
for x in s:
    print(x)
s.remove(8)
print('s = {}'.format(s))