code: def update(self) -> None:
          
          for subpars in self.secondary_subpars:
              for par in subpars:
                  try:
                      par.update()
                  except BaseException:
                      objecttools.augment_excmessage(
                          f'While trying to update parameter '
                          f'`{objecttools.elementphrase(par)}`')
docs: Call method |Parameter.update| of all "secondary" parameters.
  
          Directly after initialisation, neither the primary (`control`)
          parameters nor the secondary (`derived`)  parameters of
          application model |hstream_v1| are ready for usage:
  
          >>> from hydpy.models.hstream_v1 import *
          >>> parameterstep('1d')
          >>> simulationstep('1d')
          >>> derived
          nmbsegments(?)
          c1(?)
          c3(?)
          c2(?)
  
          Trying to update the values of the secondary parameters while the
          primary ones are still not defined, raises errors like the following:
  
          >>> model.parameters.update()
          Traceback (most recent call last):
          ...
          AttributeError: While trying to update parameter ``nmbsegments` \
  of element `?``, the following error occurred: For variable `lag`, \
  no value has been defined so far.
  
          With proper values both for parameter |hstream_control.Lag| and
          |hstream_control.Damp|, updating the derived parameters succeeds:
  
          >>> lag(0.0)
          >>> damp(0.0)
          >>> model.parameters.update()
          >>> derived
          nmbsegments(0)
          c1(0.0)
          c3(0.0)
          c2(1.0)