code: def copy(self):
      if self.is_singleton():
          x = self.__class__()
          value = self.singleton()
          x[None] = value.copy() if hasattr(value, "copy") else value
      else:
          x = self.__class__(
              (
                  (
                      name,
                      (
                          value.copy()
                          if hasattr(value, "copy")
                          else value
                      ),
                  )
                  for name, value in super().items()
              )
          )
      super(NestedDict, x).__setattr__("value_type", self.value_type)
      super(NestedDict, x).__setattr__("overwrite", self.overwrite)
      return x
  
imports: from collections import OrderedDict
  from tensorforce import TensorforceError
label_desc: Use image node_id 3 for calling the NestedDict obj's underlying member method code with example usage: obj.copy() and returns: x