def build_message(parts):
    """Join many parts to one message with a seperator

    A message will look like

    b'foo²êÀbar²êÀfoobar'

    so that it could easily splitted by .split

    parts has to be a tuple of bytestrings

    """
    msg = b''
    for i in parts[:-1]:
        msg += i
        msg += b'\xb2\xea\xc0'
    msg += parts[-1]
    return msg
