title: Failed to use cv2.TrackerMOSSE_create() and other methods in openCV [Python]
body: <p>I'm trying to perform a simple object detection using OpenCV in Python. My problem is that I cannot use TrackerMOSSE_create method as if it not exists.</p>
  <p>I've only installed opencv-contrib-python package using <code>pip install opencv-contrib-python</code>and I'm aware that it cannot coexist with the opencv-python in one virtual env so I dont have that one.</p>
  <p>I'm working on MAC and Python 3.8. There is a code below.</p>
  <pre><code>import cv2
  
  
  print(cv2.__version__)
  
  cap = cv2.VideoCapture(0)
  
  tracker = cv2.TrackerMOSSE_create()
  
  
  while True:
  
      timer = cv2.getTickCount()
      success, img = cap.read()
  
      fps = cv2.getTickFrequency() / (cv2.getTickCount() - timer)
  
      cv2.putText(img, str(int(fps)), (75, 50), cv2.FONT_ITALIC, 0.7, (0, 0, 255), 2)
      cv2.imshow(&quot;Tracking&quot;, img)
  
      if cv2.waitKey(1) &amp; 0xff == ord('q'):
          break
  
  </code></pre>
  <p>The error I have:</p>
  <pre><code>Traceback (most recent call last):
    File &quot;/Users/marcin94/PycharmProjects/tracker_objects/main.py&quot;, line 8, in &lt;module&gt;
      tracker = cv2.TrackerMOSSE_create()
  AttributeError: module 'cv2.cv2' has no attribute 'TrackerMOSSE_create'
  </code></pre>