OpenNMT-tf serving with latest prediction_service_pb2_grpc for translation

Receiving a gRPC status code of INVALID_ARGUMENT on running the code at result=future.result()
status = StatusCode.INVALID_ARGUMENT
details = “Expects arg[0] to be string but float is provided”
debug_error_string = “{“created”:”@1543318892.763504361",“description”:“Error received from peer”,“file”:“src/core/lib/surface/”,“file_line”:1017,“grpc_message”:“Expects arg[0] to be string but float is provided”,“grpc_status”:3}"

Is this error coming from or it is code you wrote?

This is the same code as examples/serving/