code: def load_ext(self):
          
          try:
              sequencemanager = hydpy.pub.sequencemanager
          except AttributeError:
              raise RuntimeError(
                  'The time series of sequence %s cannot be loaded.  Firstly, '
                  'you have to prepare `pub.sequencemanager` correctly.'
                  % objecttools.devicephrase(self))
          sequencemanager.load_file(self)
docs: Read the internal data from an external data file.