code: def verify(self):
          
          self.init.verify()
          self.sim.verify()
          if self.init.firstdate > self.sim.firstdate:
              raise ValueError(
                  f'The first date of the initialisation period '
                  f'({self.init.firstdate}) must not be later '
                  f'than the first date of the simulation period '
                  f'({self.sim.firstdate}).')
          elif self.init.lastdate < self.sim.lastdate:
              raise ValueError(
                  f'The last date of the initialisation period '
                  f'({self.init.lastdate}) must not be earlier '
                  f'than the last date of the simulation period '
                  f'({self.sim.lastdate}).')
          elif self.init.stepsize != self.sim.stepsize:
              raise ValueError(
                  f'The initialization stepsize ({self.init.stepsize}) '
                  f'must be identical with the simulation stepsize '
                  f'({self.sim.stepsize}).')
          else:
              try:
                  self.init[self.sim.firstdate]
              except ValueError:
                  raise ValueError(
                      'The simulation time grid is not properly '
                      'alligned on the initialization time grid.')
docs: Raise an |ValueError| it the different time grids are
          inconsistent.