def ctypes(self):
        """
        A ctypes function object representing the C callback.
        """
        ctypes_args = [to_ctypes(ty) for ty in self._sig.args]
        ctypes_restype = to_ctypes(self._sig.return_type)
        functype = ctypes.CFUNCTYPE(ctypes_restype, *ctypes_args)
        return functype(self.address)

        A ctypes function object representing the C callback.
        
numba/core/ccallback.py