def get_tracks(self, catalog, cache=True):
        """Get the tracks for a song given a catalog.
        
        Args:
            catalog (str): a string representing the catalog whose track you want to retrieve.
        
        Returns:
            A list of Track dicts.
        
        Example:
            >>> s = song.Song('SOWDASQ12A6310F24F')
            >>> s.get_tracks('7digital')[0]
            {u'catalog': u'7digital',
             u'foreign_id': u'7digital:track:8445818',
             u'id': u'TRJGNNY12903CC625C',
             u'preview_url': u'http://previews.7digital.com/clips/34/8445818.clip.mp3',
             u'release_image': u'http://cdn.7static.com/static/img/sleeveart/00/007/628/0000762838_200.jpg'}
            >>> 

        """
        if not (cache and ('tracks' in self.cache) and (catalog in [td['catalog'] for td in self.cache['tracks']])):
            kwargs = {
                'bucket':['tracks', 'id:%s' % catalog],
            }
                        
            response = self.get_attribute('profile', **kwargs)
            if not 'tracks' in self.cache:
                self.cache['tracks'] = []
            # don't blow away the cache for other catalogs
            potential_tracks = response['songs'][0].get('tracks', [])
            existing_track_ids = [tr['foreign_id'] for tr in self.cache['tracks']]
            new_tds = filter(lambda tr: tr['foreign_id'] not in existing_track_ids, potential_tracks)
            self.cache['tracks'].extend(new_tds)
        return filter(lambda tr: tr['catalog']==util.map_idspace(catalog), self.cache['tracks'])
Get the tracks for a song given a catalog.
        
        Args:
            catalog (str): a string representing the catalog whose track you want to retrieve.
        
        Returns:
            A list of Track dicts.
        
        Example:
            >>> s = song.Song('SOWDASQ12A6310F24F')
            >>> s.get_tracks('7digital')[0]
            {u'catalog': u'7digital',
             u'foreign_id': u'7digital:track:8445818',
             u'id': u'TRJGNNY12903CC625C',
             u'preview_url': u'http://previews.7digital.com/clips/34/8445818.clip.mp3',
             u'release_image': u'http://cdn.7static.com/static/img/sleeveart/00/007/628/0000762838_200.jpg'}
            >>>