code: def __init__(self, sample_count=10):
      self._weights = np.array([-10, -10, -10, -10])
      self._grad = np.array([1, 1, 1, 1])
      self._sample_count = sample_count
      self.obs_filter = MeanStdFilter(())
      self.rew_filter = MeanStdFilter(())
      self.filters = {
          "obs_filter": self.obs_filter,
          "rew_filter": self.rew_filter,
      }
  
file_path: ray/rllib/tests/mock_worker.py
imports: import numpy
  import ray
  from ray.rllib.evaluation.worker_set import WorkerSet
  from ray.rllib.policy.sample_batch import SampleBatch
  from ray.rllib.utils.filter import MeanStdFilter
label_desc: Use image node_id 1 to create a new _MockWorker object  with example: obj = _MockWorker(sample_count)