code: def unique_values(
      x: Union[(None, mx.ndarray.NDArray)],
      /,
      *,
      out: Optional[Union[(None, mx.ndarray.NDArray)]] = None,
  ) -> Union[(None, mx.ndarray.NDArray)]:
      raise IvyNotImplementedException()
  
imports: from typing import Tuple, Union, Optional
  import mxnet
  from ivy.utils.exceptions import IvyNotImplementedException
label_desc: Use image node_id 4 for calling a global function with example usage: unique_values() without return types