Generate Graph file in the output folder.

def update(self, stats):
        """Generate Graph file in the output folder."""

        if self.generate_every != 0 and self._timer.finished():
            self.args.generate_graph = True
            self._timer.reset()

        if not self.args.generate_graph:
            return

        plugins = stats.getPluginsList()
        for plugin_name in plugins:
            plugin = stats._plugins[plugin_name]
            if plugin_name in self.plugins_to_export():
                self.export(plugin_name, plugin.get_export_history())

        logger.info("Graphs created in the folder {}".format(self.path))
        self.args.generate_graph = False