code: def test_s2s_forecaster_fit_loader_val(self):
      train_loader, val_loarder, _ = create_data(loader=True)
      forecaster = Seq2SeqForecaster(
          past_seq_len=24,
          future_seq_len=5,
          input_feature_num=1,
          output_feature_num=1,
          loss="mae",
          lr=0.01,
      )
      val_loss = forecaster.fit(train_loader, val_loarder, epochs=10)
  
imports: import numpy
  import tempfile
  import os
  from bigdl.chronos.utils import LazyImport
  from unittest import TestCase
  import pytest
  from ..None import op_torch, op_distributed, op_inference, op_automl
label_desc: Use image node_id 17 for calling the TestChronosModelSeq2SeqForecaster obj's underlying member method code with example usage: obj.test_s2s_forecaster_fit_loader_val() without return types