code: def _validate(self):
      validator = validators.ValidKey()
  
      return validator(self.form_mock, self.form_field_mock)
  
imports: from __future__ import annotations
  from unittest import mock
  import pytest
  from airflow.www import validators
label_desc: Use image node_id 2 for calling the TestValidKey obj's underlying member method code with example usage: obj._validate() and returns: validator