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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_playlist_songs(self, playlist_id, limit=1000):
 """Get a playlists's all songs. :params playlist_id: playlist id. :params limit: length of result returned by weapi. :return: a list of Song object. """


        url = 'http://music.163.com/weapi/v3/playlist/detail?csrf_token='
        csrf = ''
        params = {'id': playlist_id, 'offset': 0, 'total': True,
                  'limit': limit, 'n': 1000, 'csrf_token': csrf}
        result = self.post_request(url, params)

        songs = result['playlist']['tracks']
        songs = [Song(song['id'], song['name']) for song in songs]
        return songs