def _check_expected_inputs(self, kwargs):
        """
        Check that all kwargs are one of the following:

        - system inputs (non-attributes)
        - op inputs (self._input_types.keys())
        """
        non_attributes = [
            "name",
            "symbolic_datatype",
            "datatype",
            "symbolic_value",
            "value",
            "version",
            "before_op",
            "no_check_var_types",
            # no_check_var_types==True to force set inputs, even if type does not match with earlier ones
            "enclosing_block",
            "scopes",
        ]
        for k in kwargs.keys():
            if k not in non_attributes and k not in self._input_types:
                raise ValueError(
                    "Unknown input '{}' for op '{}'".format(k, self.op_type)
                )

        Check that all kwargs are one of the following:

        - system inputs (non-attributes)
        - op inputs (self._input_types.keys())
        
coremltools/converters/mil/mil/operation.py