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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 get_class_from_settings_from_apps(settings_key):
 """Try and get a class from a settings path by lookin in installed apps. """

    cls_path = getattr(settings, settings_key, None)

    if not cls_path:
        raise NotImplementedError()

    try:
        app_label = cls_path.split('.')[-2]
        model_name = cls_path.split('.')[-1]
    except ValueError:
        raise ImproperlyConfigured("{0} must be of the form "
                                   "'app_label.model_name'".format(
                                                                settings_key))

    app = apps.get_app_config(app_label).models_module

    if not app:
        raise ImproperlyConfigured("{0} setting refers to an app that has not "
                                   "been installed".format(settings_key))

    return getattr(app, model_name)