def _load_script(self):
        """Loads the script from the filesystem

        :raises exceptions.IOError: if the script file could not be opened
        """
        script_text = filesystem.read_file(self.path, self.filename)

        if not script_text:
            raise IOError("Script file could not be opened or was empty: {0}"
                          "".format(os.path.join(self.path, self.filename)))
        self.script = script_text