Check if a particular symmetry operation is a valid symmetry operation
        for a molecule, i.e., the operation maps all atoms to another
        equivalent atom.

        Args:
            symmop (SymmOp): Symmetry operation to test.

        Returns:
            (bool): Whether SymmOp is valid for Molecule.

def is_valid_op(self, symmop):
        """
        Check if a particular symmetry operation is a valid symmetry operation
        for a molecule, i.e., the operation maps all atoms to another
        equivalent atom.

        Args:
            symmop (SymmOp): Symmetry operation to test.

        Returns:
            (bool): Whether SymmOp is valid for Molecule.
        """
        coords = self.centered_mol.cart_coords
        for site in self.centered_mol:
            coord = symmop.operate(site.coords)
            ind = find_in_coord_list(coords, coord, self.tol)
            if not (len(ind) == 1
                    and self.centered_mol[ind[0]].species
                    == site.species):
                return False
        return True