AttributeValidator Pass Nulls

import fme
import fmeobjects
import re

def processFeature(feature):
    validation = feature.getAttribute('_fme_validation_message_list{}')
    for v in validation:
        a = re.search('(?<=\').*?(?=\')',v)
        isNull, Missing, type = feature.getAttributeNullMissingAndType(a.group(0)) 
        if isNull:
            validation.remove(v)
    feature.removeAttribute('_fme_validation_message_list{}')
    feature.removeAttribute('_fme_validation_message')
    feature.setAttribute("numbererrors",len(validation))
    if len(validation)>0:

        feature.setAttribute('_fme_validation_message_list{}',validation)

Dug out the example (my python skills are fairly basic so no doubt this could be better). The main thing for my use case was I had to distinguish between nulls which were valid and empty or missing attributes which were not. In the validation message null, empty and missing are all displayed as ‘’ and can’t be distinguished from each other.