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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_default_database(self):
 """DEPRECATED - Get the database named in the MongoDB connection URI. Useful in scripts where you want to choose which database to use based only on the URI in a configuration file. .. versionchanged:: 3.5 Deprecated, use :meth:`get_database` instead. """

        warnings.warn("get_default_database is deprecated. Use get_database "
                      "instead.", DeprecationWarning, stacklevel=2)
        if self.__default_database_name is None:
            raise ConfigurationError('No default database defined')

        return self[self.__default_database_name]