code: def test_register(self):
      register_policyeval_udafs()
  
imports: import pyspark
  import unittest
  from synapse.ml.policyeval.PolicyEvalUtil import register_policyeval_udafs
label_desc: Use image node_id 1 for calling the VowpalWabbitPolicyEval obj's underlying member method code with example usage: obj.test_register() without return types