code: def split_shard(self, project_name, logstore_name, shardId, split_hash):
          
  
          headers = {}
          params = {"action": "split", "key": split_hash}
          resource = "/logstores/" + logstore_name + "/shards/" + str(shardId)
          (resp, header) = self._send("POST", project_name, None, resource, params, headers)
          return ListShardResponse(resp, header)
docs: split a  readwrite shard into two shards
          Unsuccessful opertaion will cause an LogException.
  
          :type project_name: string
          :param project_name: the Project name 
  
          :type logstore_name: string
          :param logstore_name: the logstore name
          
          :type shardId: int
          :param shardId: the shard id
  
          :type split_hash: string
          :param split_hash: the internal hash between the shard begin and end hash
  
          :return: ListShardResponse
          
          :raise: LogException