Python client can not set metadata on metric

[pakokol]

I have been trying to set the metadata for a metric in the Python client library. Would anyone be able to help me with this?

My testing code for creating payload is:

# Publish birth for first metric
 print('Publish birth')
 columns = ["Timestamp", "ACC_X"]
 types = [DataSetDataType.UInt64, DataSetDataType.Double]
 # Periodically publish some new data
 payload = getDdataPayload()

 metaData_dsc = "My metadata description"
 payload.MetaData.description = metaData_dsc
 payload.MetaData.content_type = "xml"
 payload.MetaData.size = len(metaData_dsc)

 name = "Test metric"
 alias = 0
 metric = payload.metrics.add()
 if name is not None:
     metric.name = name
 if alias is not None:
     metric.alias = alias
 metric.timestamp = int(round(time.time() * 1000))
 metric.datatype = MetricDataType.DataSet

 # Set up the dataset
 metric.dataset_value.num_of_columns = len(types)
 metric.dataset_value.columns.extend(columns)
 metric.dataset_value.types.extend(types)

 byteArray = bytearray(payload.SerializeToString())

In the debugger, I can see that the values for MetaData are set, but when serializing they are omitted.