Add function Validate that creates an error when a condition is not met (#221)

errors.go

@@ -6,6 +6,14 @@ import (
 	"reflect"
 )
 
+// Validate is a helper that creates an error when a condition is not met.
+func Validate(ok bool, format string, args ...any) error {
+	if !ok {
+		return errors.New(fmt.Sprint(format, args))
+	}
+	return nil
+}
+
 func messageFromMsgAndArgs(msgAndArgs ...interface{}) string {
 	if len(msgAndArgs) == 1 {
 		if msgAsStr, ok := msgAndArgs[0].(string); ok {