code: def as_stream(self):
          
  
          if not self.singular:
              raise ArgumentError("Attempted to convert a non-singular selector to a data stream, it matches multiple", selector=self)
  
          return DataStream(self.match_type, self.match_id, self.match_spec == DataStreamSelector.MatchSystemOnly)
docs: Convert this selector to a DataStream.
  
          This function will only work if this is a singular selector that
          matches exactly one DataStream.