code: def empty(self, duration):
          '''Empty vector annotations.
  
          This returns an annotation with a single observation
          vector consisting of all-zeroes.
  
          Parameters
          ----------
          duration : number >0
              Length of the track
  
          Returns
          -------
          ann : jams.Annotation
              The empty annotation
          '''
          ann = super(VectorTransformer, self).empty(duration)
  
          ann.append(time=0, duration=duration, confidence=0,
                     value=np.zeros(self.dimension, dtype=np.float32))
          return anf empty(self, duration):
          '''Empty vector annotations.
  
          This returns an annotation with a single observation
          vector consisting of all-zeroes.
  
          Parameters
          ----------
          duration : number >0
              Length of the track
  
          Returns
          -------
          ann : jams.Annotation
              The empty annotation
          '''
          ann = super(VectorTransformer, self).empty(duration)
  
          ann.append(time=0, duration=duration, confidence=0,
                     value=np.zeros(self.dimension, dtype=np.float32))
          return ann
docs: Empty vector annotations.
  
          This returns an annotation with a single observation
          vector consisting of all-zeroes.
  
          Parameters
          ----------
          duration : number >0
              Length of the track
  
          Returns
          -------
          ann : jams.Annotation
              The empty annotation