code: def backup(self):
          
          count = 0
          name = "{}.bkp".format(self.filename)
          backup = os.path.join(self.cwd, name)
          while os.path.exists(backup):
              count += 1
              name = "{}.bkp{}".format(self.filename, count)
              backup = os.path.join(self.cwd, name)
          self.hey("Moving existing {} to {}".format(self.filename, name))
          os.rename(os.path.join(self.cwd, self.filename), backup)
docs: Backups files with the same name of the instance filename