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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:
 async def bootstrap(self, addrs):
 """ Bootstrap the server by connecting to other known nodes in the network. Args: addrs: A `list` of (ip, port) `tuple` pairs. Note that only IP addresses are acceptable - hostnames will cause an error. """

        log.debug("Attempting to bootstrap node with %i initial contacts",
                  len(addrs))
        cos = list(map(self.bootstrap_node, addrs))
        gathered = await asyncio.gather(*cos)
        nodes = [node for node in gathered if node is not None]
        spider = NodeSpiderCrawl(self.protocol, self.node, nodes,
                                 self.ksize, self.alpha)
        return await spider.find()