) -> Dict[str, Any]:
        """Create a message for an email."""
        mime_message = MIMEMultipart()
        mime_message.attach(MIMEText(message, "html"))
        mime_message["To"] = ", ".join(to if isinstance(to, list) else [to])
        mime_message["Subject"] = subject
        if cc is not None:
            mime_message["Cc"] = ", ".join(cc if isinstance(cc, list) else [cc])
        if bcc is not None:
            mime_message["Bcc"] = ", ".join(bcc if isinstance(bcc, list) else [bcc])
        encoded_message = base64.urlsafe_b64encode(mime_message.as_bytes()).decode()
        return {"raw": encoded_message}
    def _run(
        self,
        message: str,
        to: Union[str, List[str]],
        subject: str,
        cc: Optional[Union[str, List[str]]] = None,
        bcc: Optional[Union[str, List[str]]] = None,
        run_manager: Optional[CallbackManagerForToolRun] = None,
    ) -> str:
        """Run the tool."""
        try:
            create_message = self._prepare_message(message, to, subject, cc=cc, bcc=bcc)
            send_message = (
                self.api_resource.users()
                .messages()
                .send(userId="me", body=create_message)
            )
            sent_message = send_message.execute()
            return f'Message sent. Message Id: {sent_message["id"]}'
        except Exception as error:
            raise Exception(f"An error occurred: {error}")