code: def test_invalid_data_set(self):
      # infer dtype str
      a = tc.SArray(["str", None])
      b = tc.SArray(["str", "str"])
      # target contains none
      sf = tc.SFrame({"a": a, "b": b})
      with self.assertRaises(ToolkitError):
          tc.text_classifier.create(
              sf, target="a", features=["b"], word_count_threshold=1
          )
      # feature contains none, Github #2402
      sf = tc.SFrame({"b": a, "a": b})
      with self.assertRaises(ToolkitError):
          tc.text_classifier.create(
              sf, target="b", features=["a"], word_count_threshold=1
          )
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import unittest
  import tempfile
  import turicreate
  from turicreate.toolkits._main import ToolkitError
  from turicreate.toolkits._internal_utils import _mac_ver
  from .None import util
  import sys
label_desc: Use image node_id 4 for calling the TextClassifierCreateTests obj's underlying member method code with example usage: obj.test_invalid_data_set() without return types