How to use the pyorbital.geoloc_instrument_definitions.avhrr function in pyorbital

def get_lonlats(self):
        if self.lons is not None and self.lats is not None:
            return self.lons, self.lats
        from pyorbital.orbital import Orbital
        from pyorbital.geoloc import compute_pixels, get_lonlatalt
        from pyorbital.geoloc_instrument_definitions import avhrr

        if self.times is None:
            self.times = time_seconds(self._data["timecode"], self.year)
        scanline_nb = len(self.times)
        scan_points = np.arange(0, 2048, 32)
        # scan_points = np.arange(2048)

        sgeom = avhrr(scanline_nb, scan_points, apply_offset=False)
        # no attitude error
        rpy = [0, 0, 0]
        s_times = sgeom.times(
            self.times[:, np.newaxis]).ravel()
        # s_times = (np.tile(sgeom._times[0, :], (scanline_nb, 1)).astype(
        #    'timedelta64[s]') + self.times[:, np.newaxis]).ravel()

        orb = Orbital(self.platform_name)

        pixels_pos = compute_pixels(orb, sgeom, s_times, rpy)
        lons, lats, alts = get_lonlatalt(pixels_pos, s_times)
        self.lons, self.lats = geo_interpolate(
            lons.reshape((scanline_nb, -1)), lats.reshape((scanline_nb, -1)))

        return self.lons, self.lats