Combine the plate value(s) with the parent plate value(s)
        :param parent_plate_value: The parent plate value(s)
        :param plate_value: The plate value(s)
        :return: The combined plate values

def combine_values(parent_plate_value, plate_value):
        """
        Combine the plate value(s) with the parent plate value(s)
        :param parent_plate_value: The parent plate value(s)
        :param plate_value: The plate value(s)
        :return: The combined plate values
        """
        if parent_plate_value:
            if isinstance(plate_value[0], string_types):
                combined_plate_value = parent_plate_value + (plate_value,)
            elif isinstance(plate_value[0], tuple):
                combined_plate_value = parent_plate_value + plate_value
            else:
                raise TypeError("Unknown plate value type")
        else:
            combined_plate_value = plate_value

        return tuple(sorted(combined_plate_value))