Get undefined when the refetch function has successfully worked

 await refetchDocument();
 if (fetchDocumentError) throw fetchDocumentError;
 console.log("existingDocument");
 if (existingDocument?.checksum === checksum) return;

 if (existingDocument !== undefined || existingDocument !== null) {
     await deleteSections({ documentId: existingDocument!.id });
     if (deleteSectionsError) throw deleteSectionsError;
 }