code: def update(self):
          
          con = self.subpars.pars.control
          der = self.subpars
          for (toy, qs) in con.q:
              setattr(self, str(toy), 2.*con.v+der.seconds/der.nmbsubsteps*qs)
          self.refresh()
docs: Calulate the auxilary term.
  
          >>> from hydpy.models.llake import *
          >>> parameterstep('1d')
          >>> simulationstep('12h')
          >>> n(3)
          >>> v(0., 1e5, 1e6)
          >>> q(_1=[0., 1., 2.], _7=[0., 2., 5.])
          >>> maxdt('12h')
          >>> derived.seconds.update()
          >>> derived.nmbsubsteps.update()
          >>> derived.vq.update()
          >>> derived.vq
          vq(toy_1_1_0_0_0=[0.0, 243200.0, 2086400.0],
             toy_7_1_0_0_0=[0.0, 286400.0, 2216000.0])