package main import ( "errors" "fmt" ) var ErrDatabaseProblem = errors.New("database problem") func GetDataFromDB() error { return fmt.Errorf("failed to get data: %w", ErrDatabaseProblem) } func main() { err := GetDataFromDB() if errors.Is(err, ErrDatabaseProblem) { fmt.Println(err.Error()) } else { fmt.Println("unknown error") } }