Kapacitor UDF is giving read error: bad wiretype for oneof field in *udf.Response

The environment is Ubuntu and python 2.7 with protobuf protobuf==3.0.0b2 installed. However I am getting an error
The tick script is
var data = stream
|from()
.database('RData')
.retentionPolicy('autogen')
.measurement('Test')
data
@EuclAnamoly()
.field('AX1')
.size(10)
The field AX1 is part of the measurement 'Test' in influx db database RData

In the UDF for info section following is the code
def info(self):
response = udf_pb2.Response()
response.info.wants = udf_pb2.STREAM
response.info.provides = udf_pb2.STREAM
response.info.options['size'].valueTypes.append(udf_pb2.INT)
response.info.options['field'].valueTypes.append(udf_pb2.STRING)
return response

Not sure why the error read error: bad wiretype for oneof field in *udf.Response is being thrown.

Reproduce the failure with the provided Ubuntu, Python 2.7, protobuf 3.0.0b2 environment, tick script, and UDF info(self) implementation. Start at udf_pb2.Response and the STREAM option declarations; done means the UDF can be loaded and the stream with the size and field options runs without the bad wiretype error.

Written by the indexing model from the issue text.