def _prepare_headers(
        self,
        headers: Optional[Dict[str, str]] = None,
    ) -> Dict[str, str]:
        """
        Construct and return the headers for a request.

        Args:
            headers (Optional[Dict[str, str]]): HTTP headers to include in the request.

        Returns:
            Dict[str, str]: The prepared headers.

        """
        return {**(self.default_headers or {}), **(headers or {})}

        Construct and return the headers for a request.

        Args:
            headers (Optional[Dict[str, str]]): HTTP headers to include in the request.

        Returns:
            Dict[str, str]: The prepared headers.

        
llama-index-integrations/llms/llama-index-llms-oci-data-science/llama_index/llms/oci_data_science/base.py