docs: def save(self, path="speech"):
          """Save data in file.
  
          Args:
              path (optional): A path to save file. Defaults to "speech".
                  File extension is optional. Absolute path is allowed.
  
          Returns:
              The path to the saved file.
          """
          if self._data is None:
              raise Exception("There's nothing to save")
  
          extension = "." + self.__params["format"]
          if os.path.splitext(path)[1] != extension:
              path += extension
  
          with open(path, "wb") as f:
              for d in self._data:
                  f.write(d)
  
          return path