Shift Cipher

shift_3.py

class ShiftCipher:
    [...]

import sys

if __name__ == "__main__":
    if len(sys.argv) < 3:
        print("Not enough arguments, please provide e/d followed by the message")
    N = 13
    cipher = ShiftCipher(N)

    if sys.argv[1] == "e":
        message = cipher.encrypt_message(sys.argv[2])
        print("Encrypted message: \n {}".format(message))
    elif sys.argv[1] == "d":
        message = cipher.decrypt_message(sys.argv[2])
        print("Decrypted message: \n {}".format(message))