def decode_arguments(self, builder, argtypes, func):
        """
        Get the decoded (unpacked) Python arguments with *argtypes*
        from LLVM function *func*.  A tuple of LLVM values is returned.
        """
        raw_args = self.get_arguments(func)
        arginfo = self._get_arg_packer(argtypes)
        return arginfo.from_arguments(builder, raw_args)

        Get the decoded (unpacked) Python arguments with *argtypes*
        from LLVM function *func*.  A tuple of LLVM values is returned.
        
numba/core/callconv.py