code: def trim(self, lower=None, upper=None):
          
          pwmax = self.subseqs.seqs.model.parameters.control.pwmax
          wats = self.subseqs.wats
          if upper is None:
              upper = pwmax*wats
          lland_sequences.State1DSequence.trim(self, lower, upper)
docs: Trim values in accordance with :math:`WAeS \\leq PWMax \\cdot WATS`.
  
          >>> from hydpy.models.lland import *
          >>> parameterstep('1d')
          >>> nhru(7)
          >>> pwmax(2.)
          >>> states.wats = 0., 0., 0., 5., 5., 5., 5.
          >>> states.waes(-1., 0., 1., -1., 5., 10., 20.)
          >>> states.waes
          waes(0.0, 0.0, 0.0, 0.0, 5.0, 10.0, 10.0)