protected override async Task <ConceptOneOptional> AssignUpsertedReferences(ConceptOneOptional record)
        {
            record.Concept1 = await _concepts.UpsertAsync(record.Concept1);

            record.Concept1Id = record.Concept1?.ConceptId ?? record.Concept1Id;
            record.Concept2   = await _concepts.UpsertAsync(record.Concept2);

            record.Concept2Id = record.Concept2?.ConceptId ?? record.Concept2Id;
            return(record);
        }
 protected override Expression <Func <ConceptOneOptional, bool> > FindExisting(ConceptOneOptional record)
 => existing
 => existing.Concept1Id == record.Concept1Id &&
 existing.Concept2Id == record.Concept2Id;
        protected override IEnumerable <object> EnumerateReferences(ConceptOneOptional record)
        {
            yield return(record.Concept1);

            yield return(record.Concept2);
        }