code: def calculate_single_terms(self):
          
          self.numvars.nmb_calls = self.numvars.nmb_calls+1
          for method in self.PART_ODE_METHODS:
              method(self)
docs: Apply all methods stored in the hidden attribute
          `PART_ODE_METHODS`.
  
          >>> from hydpy.models.test_v1 import *
          >>> parameterstep()
          >>> k(0.25)
          >>> states.s = 1.0
          >>> model.calculate_single_terms()
          >>> fluxes.q
          q(0.25)