code: def test_nbeats_forecaster_fit_loader_val(self):
      train_loader, val_loader, _ = create_data(loader=True)
      forecater = NBeatsForecaster(
          past_seq_len=24, future_seq_len=5, loss="mae", lr=0.01
      )
      val_loss = forecater.fit(train_loader, val_loader, epochs=10)
  
imports: import os
  import tempfile
  import numpy
  from unittest import TestCase
  import pytest
  from bigdl.chronos.utils import LazyImport
  from ..None import op_torch, op_distributed, op_inference, op_automl
label_desc: Use image node_id 19 for calling the TestChronosNBeatsForecaster obj's underlying member method code with example usage: obj.test_nbeats_forecaster_fit_loader_val() without return types