def __init__(self, filename):
        """
        Initialize the internal structures of the parser Base
        :param filename: path to the database file
        """

        self.db_file_name = None

        if isinstance(filename, str):
            if os.path.isfile(filename):
                self.db_file_name = filename

            else:
                raise FileNotFoundError('Database file %s not found'
                                        % filename)
        else:
            raise ValueError('Unacceptable value for database file name: %s '
                             % filename)

        Initialize the internal structures of the parser Base
        :param filename: path to the database file
        
plato/domain/database.py