else:
            model = self.model_name
            if model == "gpt-3.5-turbo":
                # gpt-3.5-turbo may change over time.
                # Returning num tokens assuming gpt-3.5-turbo-0301.
                model = "gpt-3.5-turbo-0301"
            elif model == "gpt-4":
                # gpt-4 may change over time.
                # Returning num tokens assuming gpt-4-0314.
                model = "gpt-4-0314"
        # Returns the number of tokens used by a list of messages.
        try:
            encoding = tiktoken_.encoding_for_model(model)
        except KeyError:
            logger.warning("Warning: model not found. Using cl100k_base encoding.")
            model = "cl100k_base"
            encoding = tiktoken_.get_encoding(model)
        return model, encoding
[docs]    def get_token_ids(self, text: str) -> List[int]:
        """Get the tokens present in the text with tiktoken package."""
        # tiktoken NOT supported for Python 3.7 or below
        if sys.version_info[1] <= 7:
            return super().get_token_ids(text)
        _, encoding_model = self._get_encoding_model()
        return encoding_model.encode(text)
[docs]    def get_num_tokens_from_messages(self, messages: List[BaseMessage]) -> int:
        """Calculate num tokens for gpt-3.5-turbo and gpt-4 with tiktoken package.
        Official documentation: https://github.com/openai/openai-cookbook/blob/
        main/examples/How_to_format_inputs_to_ChatGPT_models.ipynb"""