def get_band_structure(self):
        """Returns calclated band structures

        Returns
        -------
        (q-points, distances, frequencies, eigenvectors)

        Each tuple element is a list containing properties on number of paths.
        The number of q-points on one path can be different from that on the
        other path. Each set of properties on a path is ndarray and is
        explained as below:

        q-points[i]: ndarray
            q-points in reduced coordinates of reciprocal space without 2pi.
            shape=(q-points, 3), dtype='double'
        distances[i]: ndarray
            Distances in reciprocal space along paths.
            shape=(q-points,), dtype='double'
        frequencies[i]: ndarray
            Phonon frequencies
            shape=(q-points, bands), dtype='double'
        eigenvectors[i]: ndarray
            Phonon eigenvectors. None if eigenvectors are not stored.
            shape=(q-points, bands, bands), dtype='complex'
        group_velocities[i]: ndarray
            Phonon group velocities. None if group velocities are not
            calculated.
            shape=(q-points, bands, 3), dtype='double'

        """

        warnings.warn("Phonopy.get_band_structure is deprecated. "
                      "Use Phonopy.get_band_structure_dict.",
                      DeprecationWarning)

        if self._band_structure is None:
            msg = ("run_band_structure has to be done.")
            raise RuntimeError(msg)

        retvals = (self._band_structure.qpoints,
                   self._band_structure.distances,
                   self._band_structure.frequencies,
                   self._band_structure.eigenvectors)
        return retvals