_______                                  _____
         |                                |
input    |------ is valid? ----- yes ---->|  output
  _______|           |                    |_____
     ^               |
     |               no
     |               |
     |_______________|

import pyblish.api as pyblish
​
class MyValidator(pyblish.InstancePlugin):
    """Documentation goes here"""
​
    order = pyblish.ValidatorOrder
​
    def process(self, instance):
        self.log.info("something")