docs: def _shift_factor(self, factor, shift):
          """
          Shifting the factor to a certain required time slice.
  
          Parameters:
          ----------
          factor: DiscreteFactor
             The factor which needs to be shifted.
  
          shift: int
             The new timeslice to which the factor should belong to.
          """
          new_scope = self._shift_nodes(factor.scope(), shift)
          return DiscreteFactor(new_scope, factor.cardinality, factor.values)