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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 configure_backup_directory(self):
 """ Configure backup directory """

        self._display_question("Please choose a directory in which to store the backup files. By default, the tool will them in the current "
                               "directory")
        backup_directory = None
        while backup_directory is None:
            backup_directory = self._ask_with_default("Backup directory", ".")
            if not os.path.exists(backup_directory):
                self._display_error("Path does not exists")
                if self._ask_boolean("Would you like to retry?", True):
                    backup_directory = None

        return {"backup_directory": backup_directory}