code: def test_filter_multiple(self):
      def _filter(s1, s2):
          return s1 != "world\n" and "test" in s2
  
      ds = self._dataset(
          ["ascii_1.txt", "ascii_2.txt"], filter_func=_filter
      )
      assert len(ds) == 2
      assert ds[0] == ("hello\n", "test file\n")
      assert ds[1] == ("test\n", "world test\n")
  
imports: from __future__ import unicode_literals
  import os
  import pickle
  import unittest
  import six
  from chainer import datasets
  from chainer import testing
label_desc: Use image node_id 19 for calling the TestTextDataset obj's underlying member method code with example usage: obj.test_filter_multiple() and returns: unknown