def _release_callbacks(self):
    'Release keys'
    self.animation.viewer.bind_key('Alt-f', None)
    self.animation.viewer.bind_key('Alt-r', None)
    self.animation.viewer.bind_key('Alt-d', None)
    self.animation.viewer.bind_key('Alt-a', None)
    self.animation.viewer.bind_key('Alt-b', None)
Release keys
def _release_callbacks(self):
    
    self.animation.viewer.bind_key('Alt-f', None)
    self.animation.viewer.bind_key('Alt-r', None)
    self.animation.viewer.bind_key('Alt-d', None)
    self.animation.viewer.bind_key('Alt-a', None)
    self.animation.viewer.bind_key('Alt-b', None)