def dag_to_file(self, dict_viz, output_file=".treeDag.json"):
        """Writes dag to output file

        Parameters
        ----------
        dict_viz: dict
            Tree like dictionary that is used to export tree data of processes
            to html file and here for the dotfile .treeDag.json

        """

        outfile_dag = open(os.path.join(dirname(self.nf_file), output_file)
                           , "w")
        outfile_dag.write(json.dumps(dict_viz))
        outfile_dag.close()
Writes dag to output file

        Parameters
        ----------
        dict_viz: dict
            Tree like dictionary that is used to export tree data of processes
            to html file and here for the dotfile .treeDag.json