rosalind Calculating Expected Offspring

def calculate_offspring(r):
    ref = [2, 2, 2, 1.5, 1, 0]
    return sum(ref[i] * r[i] for i in range(len(r)) if r[i] != 0)

def iev(path):
    with open(path) as fp:
        r = [int(i) for i in fp.readline().split()]

    return calculate_offspring(r)

print(iev(r'rosalind_iev.txt'))