def rotate(text, key):
    cyphertext: str = ""
    for letter in text:
        if letter.isalpha():
            # check if letter is uppercase or lower case,
            # and set add_value accordingly
            if ord(letter) >= ord("A") and ord(letter) <= ord("Z"):
                add_value = ord("A")
            else:
                add_value = ord("a")
            # mod_value
            mod_value = add_value + 26
            cyphertext += chr(
                ((ord(letter) + key) % mod_value)
                + (((ord(letter) + key) // mod_value) * add_value)
            )
        else:
            cyphertext += letter
    return cyphertext