code: def __iter__(self):
      for name, value in super().items():
          if name == self.__class__._SINGLETON:
              if isinstance(value, self.value_type):
                  yield None
              else:
                  yield from value
          elif isinstance(value, self.value_type):
              yield name
          else:
              assert isinstance(value, self.__class__)
              for subname in value:
                  if subname is None:
                      yield name
                  else:
                      yield "{}/{}".format(name, subname)
  
imports: from collections import OrderedDict
  from tensorforce import TensorforceError
label_desc: Use image node_id 10 for calling the NestedDict obj's underlying member method code with example usage: obj.__iter__() without return types