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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def import_settings_class(setting_name):
 """ Return the class pointed to be an app setting variable. """

    config_value = getattr(settings, setting_name)
    if config_value is None:
        raise ImproperlyConfigured("Required setting not found: {0}".format(setting_name))

    return import_class(config_value, setting_name)