higher
           than the current priority.
           For "append" options, appends the values parsed from value_string to the current list of values. If the first
           parsed element of the list of values is empty and the priority is equal to or higher than the current
           priority, the current list is replaced with the new values.
           If the priority is higher than the current priority, the current priority is increased to the priority.
           Raises dnf.exceptions.ConfigError if the option with the given name does not exist or value_string contains
           an invalid value or not allowed value.
        z