def METHOD_NAME(self):
    """
    Retrieves the model number (or part number) of the device
    Returns:
        string: Model/part number of device
    """
    model = "N/A"
    attr_path = PSU_DIR+self.psu_model_attr
    attr_rv = self.__get_attr_value(attr_path)
    if (attr_rv != 'ERR'):
        model = attr_rv
    return model 