def hook_comment(input_string: str, comment_char: str='# ') ->str:
    """
    Comment the given string

        :param input_string: The string to comment. Multi-line strings will receive a comment on each line
        :param comment_char: The character(s) to add at the beginning of each line

        :return: The commented string

        .. note:: Block-comments are not supported at the moment
    """
    return comment_char + input_string.replace('\n', '\n' + comment_char)
