code: def add_data(self, path, time_info, data, exprs):
          
          # Dont add if empty
          if not nonempty(data):
              for d in self.data[path]:
                  if nonempty(d['values']):
                      return
  
          # Add data to path
          for expr in exprs:
              self.paths[expr].add(path)
          self.data[path].append({
              'time_info': time_info,
              'values': data
          })
docs: Stores data before it can be put into a time series