It's a bad idea to access the non-error return value in case of an error, it could cause a nil pointer exception (depending on whether it's a pointer or not). It also makes reading difficult.  ```suggestion  \t\t\tframe, err := SeriesToFrame(series)  \t\t\tif err != nil {  \t\t\t\treturn nil, err  \t\t\t}  \t\t\tframe.RefID = refID  ```