Register a scan function

        Args:
            func_name: The function name of a scan function.
            func_kwargs: A dict containing arguments of the scan function.

def register_func(self, func_name, func_kwargs):
        """Register a scan function

        Args:
            func_name: The function name of a scan function.
            func_kwargs: A dict containing arguments of the scan function.
        """
        self.scan_funcs.append(func_name)
        self.scan_kwargs.append(func_kwargs)