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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def build_reply_opts(self, message):
 """ Convenience method for constructing default options for a reply message. :param message: the message to reply to :return: opts """

        try:
            source = message['metadata']['source_channel']
            thread = message['metadata'].get('thread_ts')
            opts = {'target': source, 'thread': thread}
        except LookupError:
            source = None
            opts = None
            logger.error("Could not identify source from  message:{}\n"
                         .format(str(message)))
        return opts