For this challenge, implement the simple polyalphabetic Vigenre cipher. Using the template below, implement the encrypt() and decrypt() functions. Tests have been included at the bottom of the template that can be used to verify your implementation is correct. Make sure to follow the instructions below, carefully following naming conventions where outlined.

#!/usr/bin/env python3

"""

Vigenre cipher

"""

import string

# String of all 26 alphabetical letters in uppercase

ALPHABET = string.ascii_uppercase

def encrypt(plaintext: str, key: str) -> str:

"""

TODO: Replace this with an explanation of your implementation

"""

# TODO: Replace this with your implementation

def decrypt(ciphertext: str, key: str) -> str:

"""

TODO: Replace this with an explanation of your implementation

"""

# TODO: Replace this with your implementation

if __name__ == "__main__":

# You can use this to test, or remove and do your own tests below

plaintext = "ATTACKATDAWN"

key = "LEMON"

expected = "LXFOPVEFRNHR"

ciphertext = encrypt(plaintext, key)

assert ciphertext == expected

assert plaintext == decrypt(ciphertext, key)