output.txt

sets!
one(1): True
two(2): True

Join/Or!
one_or_two(1): True
one_or_two(2): True

Intersect/And!
one_but_not_two(1): True
one_but_not_two(2): False

sets.py

def fset(n):
    return lambda x: x == n

def set_join(*fsets):
    return lambda x: any([f(x) for f in fsets])

def set_intersect(*fsets):
    return lambda x: all([f(x) for f in fsets])

one = fset(1)
two = fset(2)

print 'sets!'
assert one(1)
assert two(2)
print 'one(1):', one(1)
print 'two(2):', two(2)

print
print 'Join/Or!'
one_or_two = set_join(one, two)

assert one_or_two(1)
assert one_or_two(2)
print 'one_or_two(1):', one_or_two(1)
print 'one_or_two(2):', one_or_two(2)

print
print 'Intersect/And!'
one_but_not_two = set_intersect(one_or_two, one)

assert one_but_not_two(1)
assert not one_but_not_two(2)
print 'one_but_not_two(1):', one_but_not_two(1)
print 'one_but_not_two(2):', one_but_not_two(2)