code: def validate_vw(self):
      self.compose_vw_validate_command()
      self.logger.info(
          "executing the following command (validation): %s"
          % self.validate_command
      )
      subprocess.call(shlex.split(self.validate_command))
  
imports: from hyperopt import hp, fmin, tpe, rand, Trials, STATUS_OK
  from hyperopt.pyll import scope
  from sklearn.metrics import roc_curve, auc, log_loss, average_precision_score, hinge_loss, mean_squared_error
  import numpy
  from datetime import datetime
  import subprocess, shlex
  from math import exp, log
  import argparse
  import re
  import logging
  import json
  from matplotlib import pyplot
  import itertools
  from collections import Counter
label_desc: Use image node_id 8 for calling the HyperOptimizer obj's underlying member method code with example usage: obj.validate_vw() without return types