title: Install opencv-python module
body: <p>I'm trying to install the opencv module without success, I think the problem is related to the version of python I'm using.
  Indeed I upgraded to the 3.9.1 version but when I'm trying to install the module, I still receive a warning referred to the old version of python I had (i.e. 2.7).
  How can I get rid of this situation and successfully install the opencv library?</p>
  <p><a href="https://i.stack.imgur.com/I5LKH.png" rel="nofollow noreferrer">Error in bash</a></p>