code: def trim(self, lower=None, upper=None):
          
          if lower is None:
              lower = getattr(self.subpars.eqi2, 'value', None)
          if upper is None:
              upper = getattr(self.subpars.eqb, 'value', None)
          super().trim(lower, upper)
docs: Trim upper values in accordance with
          :math:`EQI2 \\leq EQI1 \\leq EQB`.
  
          >>> from hydpy.models.lland import *
          >>> parameterstep('1d')
          >>> eqb.value = 3.0
          >>> eqi2.value = 1.0
          >>> eqi1(0.0)
          >>> eqi1
          eqi1(1.0)
          >>> eqi1(1.0)
          >>> eqi1
          eqi1(1.0)
          >>> eqi1(2.0)
          >>> eqi1
          eqi1(2.0)
          >>> eqi1(3.0)
          >>> eqi1
          eqi1(3.0)
          >>> eqi1(4.0)
          >>> eqi1
          eqi1(3.0)