'Override this.
A trivial example is included.'

def filterMessage(self):

    try:
        emailParser = email.parser.Parser()
        with open(self.messageFilename) as f:
            emailParser.parse(f)
        self.sendLine('200    Ok')
    except:
        trace_dump()
        self.sendLine(('435    %s    processing    error' % FILTERNAME))
