code: def once(self):
          
          ns = self.Namespace()
          ns.memo = None
          ns.run = False
  
          def work_once(*args, **kwargs):
              if ns.run is False:
                  ns.memo = self.obj(*args, **kwargs)
              ns.run = True
              return ns.memo
  
          return self._wrap(work_once)
docs: Returns a function that will be executed at most one time,
          no matter how often you call it. Useful for lazy initialization.