class_docstr: A vectorized wrapper that normalizes the observations
  and returns from an environment.
code: def _obfilt(self, obs):
      if self.ob_rms:
          self.ob_rms.update(obs)
          obs = np.clip(
              (obs - self.ob_rms.mean)
              / np.sqrt(self.ob_rms.var + self.epsilon),
              -self.clipob,
              self.clipob,
          )
          return obs
      else:
          return obs
  
file_path: baselines/baselines/common/vec_env/vec_normalize.py
imports: from .None import VecEnvWrapper
  import numpy
label_desc: Use image node_id 3 for calling the VecNormalize obj's underlying member method code with example usage: obj._obfilt(obs) and returns: obs, obs