Trouble with global variables

[Larz60+]

Python does indeed have globals, but ...

Global variables are considered bad programming in all languages by seasoned programmers.

Here's one reason that kills their use (In my book):
Coupling between various methods (or functions). Assume the following:

• Method 1 sets global variable snoot to 4
  
• Method 2, which uses the contents of snoot, executes method 3 as a thread if snoot equals 4
      Upon return from the thread, it checks the content of  snoot,
      if snoot equals anything other than 4, it prints message: 'method 3 was not executed'
      otherwise it prints message: ''method 3 was successfully executed'.
  
• While the thread in method 2 was running, method 5 changed the global variable snoot to 2.
      Method2 will see the '2' when thread completes, thus prints the wrong message.
  

There are many other reasons you should avoid using globals , see: http://wiki.c2.com/?GlobalVariablesAreBad