new_contents: import time
  from concurrent import futures
  
  import grpc
  
  import calculator_pb2_grpc
  from calculator_service import CalculatorService
  
  _ONE_DAY_IN_SECONDS = 60 * 60 * 24
  
  
  def serve():
      server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
      calculator_pb2_grpc.add_CalculatorServicer_to_server(CalculatorService(), server)
      server.add_insecure_port('[::]:50051')
      server.start()
      try:
          while True:
              time.sleep(_ONE_DAY_IN_SECONDS)
      except KeyboardInterrupt:
          server.stop(0)
  
  
  if __name__ == '__main__':
      serve()
  
subject: Implement server side.