code: def onlyOnce(fn):
      'Set up FN to only run once within an interpreter instance'
      def wrap(*args, **kwargs):
          if hasattr(fn, 'called'):
              return
          fn.called = 1
          return fn(*args, **kwargs)
      util.mergeFunctionMetadata(fn, wrap)
      return wraf onlyOnce(fn):
      'Set up FN to only run once within an interpreter instance'
      def wrap(*args, **kwargs):
          if hasattr(fn, 'called'):
              return
          fn.called = 1
          return fn(*args, **kwargs)
      util.mergeFunctionMetadata(fn, wrap)
      return wrap
docs: Set up FN to only run once within an interpreter instance