code: def restart(self, start_from=1, occupied=[]):
          
  
          # initial ID
          self.top = start_from - 1
  
          # occupied IDs
          self._occupied = sorted(occupied, key=lambda x: x[0])
  
          # main dictionary storing the mapping from objects to variable IDs
          self.obj2id = collections.defaultdict(lambda: self._next())
  
          # mapping back from variable IDs to objects
          # (if for whatever reason necessary)
          self.id2obj = {}
docs: Restart the manager from scratch. The arguments replicate those of
              the constructor of :class:`IDPool`.