from lib_fibonacci import fibonacci_generator_smaller


def euler_002():
    fs = [f for f in fibonacci_generator_smaller(4000000) if f % 2 == 0]
    return sum(fs)


assert(euler_002() == 4613732)
print("e002.py: {}".format(euler_002()))


def euler_002_simple():
    """ Sometimes it is nice to keep it simple. Instead of using three
    library functions just implement one straightforward function. """
    r, a, b = 0, 0, 1
    while b < 4000000:
        if b % 2 == 0:
            r += b
        a, b = b, a + b
    return r


assert(euler_002() == euler_002_simple())