Import a model from a file.

        @param filepath: File to be imported.
        @type filepath: str

def import_from_file(self, filepath):
        """
        Import a model from a file.

        @param filepath: File to be imported.
        @type filepath: str
        """
        
        inc_dirs = self.include_directories[:]
        inc_dirs.append(dirname(filepath))
                        
        parser = LEMSFileParser(self, inc_dirs, self.include_includes)
        with open(filepath) as f:
            parser.parse(f.read())