code: def get_x_inds(self, *dynac_type):
          
          return [i for i, x in enumerate(self.lattice) for y in dynac_type if dynac_from_ele(x) == y]
docs: Return the indices into the lattice list attribute of elements whose Dynac
          type matches the input string.  Multiple input strings can be given, either
          as a comma-separated list or as a genuine Python list.