ScriptRunner how to add additional 'built-in scripts'?

[KB]

We use custom validators that are repeated on various tranisitions in the JIRA workflow. Therefore I'd like to add our scriptrunner validator to built-in validator scripts. 

I came across an example for listeners but would like to know how it can be done for Validator. 

example for listener:

@ScriptListener
class SampleScriptListener implements CannedScript {

public static String FIELD_MY_PARAM = "FIELD_MY_PARAM"

@Override
 String getName() {
 "Sample listener"
 }

@Override
 String getDescription() {
 "Sample listener from a plugin"
 }

@Override
 List getCategories() {
 [] // unused
 }

example for validator (doesn't work):

class MyFirstValidator implements CannedScript {

public static String FIELD_MY_PARAM = "FIELD_MY_PARAM"

@Override
 String getName() {
 "My Validator"
 }

@Override
 String getDescription() {
 "Sample listener from a plugin"
 }

@Override
 List getCategories() {
 ["Validator"] // unused
 }

 Is there an annotation that I need to use for validator? Do you have an example I could use?

[Nisha Hajamohideen]

Did you try the examples in https://scriptrunner.adaptavist.com/4.3.4/jira/recipes/workflow/validators/simple-scripted-validators.html

[KB]

Thanks Nisha for responding here. 

I'm afraid this is not what I was looking for. I need an example how to implement CannedScript for a validator I have created. 

So that it is available as another built-in "Script Validator" similar to "Fields(s) changed validator".