extensions/ipynb/src/notebookAttachmentCleaner.ts/AttachmentCleaner/saveAllAttachmentsToCache
class AttachmentCleaner:	private saveAllAttachmentsToCache(metadata: { [key: string]: unknown }, notebookUri: string, cellFragment: string): void {
		const documentCache = this._attachmentCache.get(notebookUri) ?? new Map();
		this._attachmentCache.set(notebookUri, documentCache);
		const cellCache = documentCache.get(cellFragment) ?? new Map<string, IAttachmentData>();
		documentCache.set(cellFragment, cellCache);

		if (metadata.attachments && typeof metadata.attachments === 'object') {
			for (const [currFilename, attachment] of Object.entries(metadata.attachments)) {
				cellCache.set(currFilename, attachment);
			}
		}
	}