import string


def to_encrypt(text, delta):
    alphabet = list(string.ascii_lowercase)
    new_text = []
    for letter in text:
        if letter.isalpha():
            letter_index = alphabet.index(letter) + delta
            if letter_index > len(alphabet):
                letter_index = letter_index - len(alphabet)
            if letter_index < 0:
                letter_index = len(alphabet) + letter_index
            new_text.append(alphabet[letter_index])
        else:
            new_text.append(letter)
    return "".join(new_text)


if __name__ == '__main__':
    print("Example:")
    print(to_encrypt('abc', 10))

    # These "asserts" using only for self-checking and not necessary for auto-testing
    assert to_encrypt("a b c", 3) == "d e f"
    assert to_encrypt("a b c", -3) == "x y z"
    assert to_encrypt("simple text", 16) == "iycfbu junj"
    assert to_encrypt("important text", 10) == "swzybdkxd dohd"
    assert to_encrypt("state secret", -13) == "fgngr frperg"
    print("Coding complete? Click 'Check' to earn cool rewards!")