in source/update_ddb_from_stream/update_ddb_from_stream.py [0:0]
def merge_values(record_data, set_data, metric_type, k):
if k not in record_data: return set_data[k]
if k not in set_data: return record_data[k]
return type_operator_map[metric_type]([set_data[k], record_data[k]])