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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 _setup(self):
 """ Load the settings module pointed to by the environment variable. This is used the first time we need any settings at all, if the user has not previously configured the settings manually. """

        settings_module = os.environ.get(ENVIRONMENT_SETTINGS_VARIABLE, 'settings')
        if not settings_module:
            raise ImproperlyConfigured(
                'Requested settings module points to an empty variable. '
                'You must either define the environment variable {0} '
                'or call settings.configure() before accessing the settings.'
                .format(ENVIRONMENT_SETTINGS_VARIABLE))

        self._wrapped = Settings(settings_module, default_settings=global_settings)