code: def test_encoder_on_cpu(self):
      self.check_encoder_on_device("cpu")
  
file_path: lightwood/tests/unit_tests/encoder/time_series/test_timeseries_rnn.py
imports: import unittest
  import numpy
  import torch
  from lightwood.encoder.time_series.rnn import TimeSeriesEncoder
  from lightwood.encoder.helpers import MinMaxNormalizer, CatNormalizer
  import pandas
label_desc: Use image node_id 5 for calling the TestRnnEncoder obj's underlying member method code with example usage: obj.test_encoder_on_cpu() without return types