def save(self, tag=None, filename=None, passphrase=None):
        """Save object to file.

        @type tag: string
        @type filename: string
        @type passphrase: string
        """
        ext, dumpFunc = self._getStyle()
        if passphrase is not None:
            raise TypeError("passphrase must be None")
            ext = 'e' + ext
        finalname, filename = self._getFilename(filename, ext, tag)
        log.msg("Saving "+self.name+" application to "+finalname+"...")
        self._saveTemp(filename, dumpFunc)
        if runtime.platformType == "win32" and os.path.isfile(finalname):
            os.remove(finalname)
        os.rename(filename, finalname)
        log.msg("Saved.")
Save object to file.

        @type tag: string
        @type filename: string
        @type passphrase: string
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/persisted/sob.py