def audio_features(self, tracks=[]):
        """ Get audio features for one or multiple tracks based upon their Spotify IDs

            .. deprecated::
            This endpoint has been removed by Spotify and is no longer available.

            Parameters:
                - tracks - a list of track URIs, URLs or IDs, maximum: 100 ids
        """
        warnings.warn(
            "You're using `audio_features(...)`, "
            "which is marked as deprecated by Spotify.",
            DeprecationWarning,
        )

        if isinstance(tracks, str):
            trackid = self._get_id("track", tracks)
            results = self._get("audio-features/?ids=" + trackid)
        else:
            tlist = [self._get_id("track", t) for t in tracks]
            results = self._get("audio-features/?ids=" + ",".join(tlist))
        # the response has changed, look for the new style first, and if
        # it's not there, fallback on the old style
        if "audio_features" in results:
            return results["audio_features"]
        else:
            return results
 Get audio features for one or multiple tracks based upon their Spotify IDs

            .. deprecated::
            This endpoint has been removed by Spotify and is no longer available.

            Parameters:
                - tracks - a list of track URIs, URLs or IDs, maximum: 100 ids
        
spotipy/client.py