code: def update_buffer(self, treebuffer, transfer_objects=False):
          
          self._buffer.update(treebuffer)
          if transfer_objects:
              self._buffer.set_objects(treebuffer)
docs: Merge items from a TreeBuffer into this Tree's TreeBuffer
  
          Parameters
          ----------
          buffer : rootpy.tree.buffer.TreeBuffer
              The TreeBuffer to merge into this Tree's buffer
  
          transfer_objects : bool, optional (default=False)
              If True then all objects and collections on the input buffer will
              be transferred to this Tree's buffer.