docstr: Multiple instances of MTCNN can be created in the same thread.
  :return:
code: def test_mtcnn_multiple_instances(self):
      """
      Multiple instances of MTCNN can be created in the same thread.
      :return:
      """
      detector_1 = MTCNN(steps_threshold=[0.2, 0.7, 0.7])
      detector_2 = MTCNN(steps_threshold=[0.1, 0.1, 0.1])
  
      ivan = cv2.imread("ivan.jpg")
  
      faces_1 = detector_1.detect_faces(ivan)
      faces_2 = detector_2.detect_faces(ivan)
  
      self.assertEqual(len(faces_1), 1)
      self.assertGreater(len(faces_2), 1)
  
file_path: mtcnn/tests/test_mtcnn.py
imports: import unittest
  import cv2
  from mtcnn.exceptions import InvalidImage
  from mtcnn import MTCNN
label_desc: Use image node_id 5 for calling the TestMTCNN obj's underlying member method code with example usage: obj.test_mtcnn_multiple_instances() without return types