code: def remove(self, bw):
          
          try:
              self.__ranges.remove(bw)
          except KeyError:
              if not bw.oneshot:
                  raise
docs: Removes a buffer watch identifier.
  
          @type  bw: L{BufferWatch}
          @param bw:
              Buffer watch identifier.
  
          @raise KeyError: The buffer watch identifier was already removed.