title: How to open a program os.system only using python 3
body: <p>I am programming a gui using tkinter. I use os.system('file extension'). when I click the button on the gui it should open the next program, but it wont because of python 2. I can use terminal and have pythem3 ./mixed_drink, and this works. Can I set up the code to make the program only run in python 3??</p>
  <pre><code>from tkinter import *
  import os
  
  ##############
  root = Tk()
  root.title('GET YO DRANK MAIN ')
  root.geometry(&quot;800x400&quot;)
  
  def  open_mixed_drinks():
     os.system(&quot;/home/pi/mixed_drinks.py&quot;)
   
  </code></pre>