code: def build(self, track, requester):
          
          try:
              self.track = track['track']
              self.identifier = track['info']['identifier']
              self.can_seek = track['info']['isSeekable']
              self.author = track['info']['author']
              self.duration = track['info']['length']
              self.stream = track['info']['isStream']
              self.title = track['info']['title']
              self.uri = track['info']['uri']
              self.requester = requester
  
              return self
          except KeyError:
              raise InvalidTrack('An invalid track was passed.')
docs: Returns an optional AudioTrack.