code: def export_scalars(self, path):
          
          if os.path.exists(path) and os.path.isfile(path):
              logging.warning('%s already exists and will be overwritten by scalar dict', path)
          with open(path, "w") as f:
              json.dump(self._scalar_dict, f)
docs: Exports to the given path an ASCII file containing all the scalars written
          so far by this instance, with the following format:
          {writer_id : [[timestamp, step, value], ...], ...}