if !cs.Valid() {
				return oi, InvalidPart{
					PartNumber: part.PartNumber,
				}
			}
			if checksumType.FullObjectRequested() {
				if err := checksum.AddPart(*cs, expPart.ActualSize); err != nil {
					return oi, InvalidPart{
						PartNumber: part.PartNumber,
						ExpETag:    "<nil>",
						GotETag:    err.Error(),
					}
				}
			}