Validating slots in rasa 2.0

Hey, @rctatman thanks for your response but i checked this out but the problem is not in the function calling. I am getting error in this:

def create_validation_function(name_of_slot):

The error is :

“Method should have "self" as first argument”

But after adding self in the function it asked for its value in method call. I got an error in the method calling i.e :

validate_pre_city=create_validation_function(name_of_slot = “pre_city”)

The error is :

No value for argument ‘self’ in method call pylint(no-value-for-parameter)

I can’t make it static as i m calling the method. So what is the correct why to do this? What i am missing in this? Can you please check this and help me to resolve this. Thank You for your valuable time .