def inputs(self):
        """
        Returns
        -------
        - inputs: Dict[str, Union[Var, Tuple[Var]]]
        """
        # Filter out InternalVar
        return {
            k: v
            for k, v in self._input_vars.items()
            if not isinstance(v, InternalVar) and v is not None
        }

        Returns
        -------
        - inputs: Dict[str, Union[Var, Tuple[Var]]]
        
coremltools/converters/mil/mil/operation.py