code: def is_last_child(self, child_pid):
          
          last_child = self.last_child
          if last_child is None:
              return False
          return last_child == child_pid
docs: Determine if 'pid' is the latest version of a resource.
  
          Resolves True for Versioned PIDs which are the oldest of its siblings.
          False otherwise, also for Head PIDs.