encrypt_shift_left.py

def encrypt_shift_left(decode_str):
    """encode the given string (a step down to next alphabest)
    a <- c
    b <- d
    ...
    k <- m
    o <- q
    e <- g
    ..
    z <- b
    """

    new_string = ''

    for decode_char in decode_str.lower():
        if decode_char.isalpha():
            ascii_value = ord(decode_char)
            new_ascii = (ascii_value + 26 - 2) if (ascii_value <= 98) else (ascii_value - 2)
            #print(new_ascii)
            new_char = chr(new_ascii)
        else:
            new_char = decode_char

        new_string = new_string + new_char
    return new_string


print(encrypt_shift_left("Hello Welcome to Python..!!"))
print(encrypt_shift_left("I am Ramesh..."))
print(encrypt_shift_left("You're reading in Medium"))
print(encrypt_shift_left("Please subscribe to my stories"))