code: def test_ndarray_train_on_batch_multi_input(self):
      x1 = np.random.rand(ModelMultiInputTest.batch_size, 1).astype(
          np.float32
      )
      x2 = np.random.rand(ModelMultiInputTest.batch_size, 1).astype(
          np.float32
      )
      y = np.random.rand(ModelMultiInputTest.batch_size, 1).astype(
          np.float32
      )
      loss = self.model.train_on_batch((x1, x2), y)
      self.assertEqual(type(loss), float)
  
imports: import numpy
  import torch
  import torch.nn
  from torch.utils.data import DataLoader
  from poutyne import Model, TensorDataset
  from tests.framework.model.base import ModelFittingTestCase, MultiIOModel
label_desc: Use image node_id 6 for calling the ModelMultiInputTest obj's underlying member method code with example usage: obj.test_ndarray_train_on_batch_multi_input() without return types