Returns True if sites are periodic images of each other.

        Args:
            other (PeriodicSite): Other site
            tolerance (float): Tolerance to compare fractional coordinates
            check_lattice (bool): Whether to check if the two sites have the
                same lattice.

        Returns:
            bool: True if sites are periodic images of each other.

def is_periodic_image(self, other, tolerance=1e-8, check_lattice=True):
        """
        Returns True if sites are periodic images of each other.

        Args:
            other (PeriodicSite): Other site
            tolerance (float): Tolerance to compare fractional coordinates
            check_lattice (bool): Whether to check if the two sites have the
                same lattice.

        Returns:
            bool: True if sites are periodic images of each other.
        """
        if check_lattice and self.lattice != other.lattice:
            return False
        if self.species != other.species:
            return False

        frac_diff = pbc_diff(self.frac_coords, other.frac_coords)
        return np.allclose(frac_diff, [0, 0, 0], atol=tolerance)