code: def _check_initial(self):
          
          if self.C_in is None:
              raise Exception("You have to specify the initial conditions first.")
          if self.scale_in is None:
              raise Exception("You have to specify the initial scale first.")
          if self.scale_high is None:
              raise Exception("You have to specify the high scale first.")
docs: Check if initial values and scale as well as the new physics scale
          have been set.