code: def test_incorrect_data(self):
      self.assertRaises(ValueError, fcm, [], 1)
  
imports: import unittest
  import matplotlib
  from pyclustering.cluster.tests.fcm_templates import fcm_test_template
  from pyclustering.cluster.fcm import fcm
  from pyclustering.samples.definitions import SIMPLE_SAMPLES, FAMOUS_SAMPLES, FCPS_SAMPLES
label_desc: Use image node_id 25 for calling the fcm_unit_tests obj's underlying member method code with example usage: obj.test_incorrect_data() without return types