def form_message(sublines, message_divider):
    """Form the message portion of speech bubble.
       Param: sublines(list): a list of the chars to go on each line in message
       Return: bubble(str): formaatted to fit inside of a bubble
    """
    bubble = ""
    bubble += message_divider
    bubble += "".join(sublines)
    bubble += message_divider
    return bubble