# add()
s = {1, 2, 3, 4, 5}
print(s)
s.add(6)
print(s)

# clear()
print()
s = {1, 2, 3, 4, 5}
print(s)
s.clear()
print(s)

# discard()
print()
s = {1, 2, 3, 4, 5}
print(s)
s.discard(5)
print(s)
s.discard(17)
print(s)

# remove()
print()
s = {1, 2, 3, 4, 5}
print(s)
s.remove(5)
print(s)
#s.remove(17)        # KeyError: 17