title: How do you declare a global constant in Python?
body: <p>I have some heavy calculations that I want to do when my program starts, and then I want to save the result (a big bumpy matrix) in memory so that I can use it again and again. My program contains multiple files and classes, and I would like to be able to access this variable from anywhere, and if possible define it as constant.</p>
  
  <p>How do you define a global constant in Python?</p>