code: func FindByPrimaryKeyTo(db *reform.Querier,
  	rec reform.Record, key interface{}) error {
  	if err := db.FindByPrimaryKeyTo(rec, key); err != nil {
  		return fmt.Errorf("failed to find %T by primary key: %s",
  			rec, err)
  	}
  	return nil
  }
docs: // FindByPrimaryKeyTo calls db.FindByPrimaryKeyTo() returning more descriptive
  // error.