title: How to make trial period for my python application?
body: <p>I have made a desktop application in kivy and able to make single executable(.app) with pyinstaller. Now I wanted to give it to customers with the trial period of 10 days or so. 
  The problem is how to make a trial version which stop working after 10 days of installation and even if the user un-install and install it again after trial period get over it should not work.
  Giving partial feature in trial version is not an option.</p>
  
  <p>Evnironment
  Mac OS and Python 2.7 with Kivy</p>