def add_message(self, key: str, message: ChatMessage) -> None:
        """
        Add a message to the end of the chat history for the given key.
        Creates a new row if the key does not exist.

        Args:
            key (str): The key specifying a row.
            message (ChatMessage): The message to add to the chat history.

        Returns:
            None

        """
        current_messages = self.get_messages(key)
        current_messages.append(message)
        self.set_messages(key, current_messages)

        Add a message to the end of the chat history for the given key.
        Creates a new row if the key does not exist.

        Args:
            key (str): The key specifying a row.
            message (ChatMessage): The message to add to the chat history.

        Returns:
            None

        
llama-index-integrations/storage/chat_store/llama-index-storage-chat-store-tablestore/llama_index/storage/chat_store/tablestore/base.py