File "/home/dev/elisa-rewrite/elisa/plugins/gtk_plugin/gtk_player_view.py", line 122, in attribute_set
    PlayerViewClass.attribute_set(self, key, value)
  File "/home/dev/elisa-rewrite/elisa/plugins/base/views/player_view.py", line 52, in attribute_set
    self.state_changed(value)
  File "/home/dev/elisa-rewrite/elisa/plugins/base/views/player_view.py", line 75, in state_changed
    self.player.volume = self.controller.model.volume
  File "/home/dev/elisa-rewrite/elisa/core/player.py", line 471, in volume__set
    self._pipeline.set_property('volume', volume)
exceptions.AttributeError: 'NoneType' object has no attribute 'set_property'

WARN  twisted                     Jul 03 10:24:47  A twisted traceback occurred. (twisted/internet/defer.py:402