def __init__(self, filename):
        """
        Initialize the internal structures of the domain
        :param filename: path to load the ontolgoy from
        """

        self.ontology_file_name = None
        self.ontology = None

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

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

        Initialize the internal structures of the domain
        :param filename: path to load the ontolgoy from
        
plato/domain/ontology.py