code: def truncate_volume(self, volume, size):
          
          return self.set_volume(volume, size=size, truncate=True)
docs: Truncate a volume to a new, smaller size.
  
          :param volume: Name of the volume to truncate.
          :type volume: str
          :param size: Size in bytes, or string representing the size of the
                       volume to be created.
          :type size: int or str
  
          :returns: A dictionary mapping "name" to volume and "size" to the
                    volume's new size in bytes.
          :rtype: ResponseDict
  
          .. warnings also::
  
              Data may be irretrievably lost in this operation.
  
          .. note::
  
              A snapshot of the volume in its previous state is taken and
              immediately destroyed, but it is available for recovery for
              the 24 hours following the truncation.