def append_holder_map(self, held_type: T.Type[mesonlib.HoldableObject], holder_type: T.Type[ObjectHolder]) -> None:
        '''
            Adds one additional mapping to the `holder_map`.

            The intended use for this function is in the `initialize` method of
            modules to register custom object holders.
        '''
        self.holder_map.update({
            held_type: holder_type
        })

            Adds one additional mapping to the `holder_map`.

            The intended use for this function is in the `initialize` method of
            modules to register custom object holders.
        
mesonbuild/interpreter/interpreter.py