def serialize(self,writer: SerializationWriter) -> None:
        """
        Serializes information the current object
        param writer: Serialization writer to use to serialize this model
        Returns: None
        """
        if writer is None:
            raise TypeError("writer cannot be null.")
        writer.write_object_value("chatInfo", self.chat_info)
        writer.write_datetime_value("endDateTime", self.end_date_time)
        writer.write_str_value("externalId", self.external_id)
        writer.write_object_value("participants", self.participants)
        writer.write_datetime_value("startDateTime", self.start_date_time)
        writer.write_str_value("subject", self.subject)
        writer.write_additional_data_value(self.additional_data)

        Serializes information the current object
        param writer: Serialization writer to use to serialize this model
        Returns: None
        
msgraph/generated/communications/online_meetings/create_or_get/create_or_get_post_request_body.py