def by_service_announcement_attachment_id(self,service_announcement_attachment_id: str) -> ServiceAnnouncementAttachmentItemRequestBuilder:
        """
        Provides operations to manage the attachments property of the microsoft.graph.serviceUpdateMessage entity.
        param service_announcement_attachment_id: The unique identifier of serviceAnnouncementAttachment
        Returns: ServiceAnnouncementAttachmentItemRequestBuilder
        """
        if service_announcement_attachment_id is None:
            raise TypeError("service_announcement_attachment_id cannot be null.")
        from .item.service_announcement_attachment_item_request_builder import ServiceAnnouncementAttachmentItemRequestBuilder

        url_tpl_params = get_path_parameters(self.path_parameters)
        url_tpl_params["serviceAnnouncementAttachment%2Did"] = service_announcement_attachment_id
        return ServiceAnnouncementAttachmentItemRequestBuilder(self.request_adapter, url_tpl_params)

        Provides operations to manage the attachments property of the microsoft.graph.serviceUpdateMessage entity.
        param service_announcement_attachment_id: The unique identifier of serviceAnnouncementAttachment
        Returns: ServiceAnnouncementAttachmentItemRequestBuilder
        
msgraph/generated/admin/service_announcement/messages/item/attachments/attachments_request_builder.py