Python HAIL CAESAR (凯撒密码) 2

def applyCoder(text, coder):
    """
    Applies the coder to the text. Returns the encoded text.


    text: string
    coder: dict with mappings of characters to shifted characters
    returns: text after mapping coder chars to original text
    """
    ### TODO.
    new = ""
    for word in text:
        if word in string.ascii_lowercase or word in string.ascii_uppercase:
            new = new + coder[word]
        else:
            new = new + word
    return new

少了红色部分一直返回 keyerror /(ㄒoㄒ)/~~