Return the path of all granules of a given band.

def granule_paths(self, band_id):
        """Return the path of all granules of a given band."""
        band_id = str(band_id).zfill(2)
        try:
            assert isinstance(band_id, str)
            assert band_id in BAND_IDS
        except AssertionError:
            raise AttributeError(
                "band ID not valid: %s" % band_id
                )
        return [
            granule.band_path(band_id)
            for granule in self.granules
            ]