def add_prefix(info_string, prefix):
    """Prefixes each line of info_string, except the first, by prefix."""
    lines = info_string.split("\n")
    prefixed_lines = [lines[0]]
    for line in lines[1:]:
        prefixed_line = ":".join([prefix, line])
        prefixed_lines.append(prefixed_line)
    prefixed_info_string = "\n".join(prefixed_lines)
    return prefixed_info_string