An attempt at a hash function

hash.py

def msum(l):
    "Product of elements in l"
    x = 1
    for i in l:
        x *= i
    return x

def make_blocks(s, size):
    "Create blocks from s of specified size"
    for i in range(0, len(s), size):
        block = s[i:i+size]
        while len(block) < size:
            block += chr(95 + len(block)) # 95: arbitrary ascii number
        yield block

def combine(blocks, block_size):
    "Combine the blocks"
    h = 1
    for block in blocks:
       h ^= msum(map(ord, block))
    return str(hex(h))[2:]

def hash_(string, block_size=16):
    blocks = make_blocks(string, block_size)
    return combine(blocks, block_size)

def main():
    print(hash_("Testing the hash function"))

if __name__ == '__main__':
    main()