code: def update(self):
          
          con = self.subpars.pars.control
          self(con.hinz*con.lai)
docs: Update |KInz| based on |HInz| and |LAI|.
  
          >>> from hydpy.models.lland import *
          >>> parameterstep('1d')
          >>> nhru(2)
          >>> hinz(0.2)
          >>> lai.acker_jun = 1.0
          >>> lai.vers_dec = 2.0
          >>> derived.kinz.update()
          >>> from hydpy import round_
          >>> round_(derived.kinz.acker_jun)
          0.2
          >>> round_(derived.kinz.vers_dec)
          0.4