Vigenere密码

def solve(____):
    key = str(____).strip()
    plain = str(____).strip()
    result = []
    ki = ____
    for c in plain:
        if c.isalpha():
            k = key[ki % len(____)]
            shift = ord(k.upper()) - ord(____)
            if c.isupper():
                result.append(chr((ord(____) - ord(____) + shift) % ____ + ord(____)))
            else:
                result.append(chr((ord(____) - ord(____) + shift) % ____ + ord(____)))
            ki += ____
        else:
            result.append(____)
    print('____'.join(____))