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.

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