Problem with -3 switch

[Aivar Annamaa]

Hi

I'm getting started with Python and in order to get good habits for 
Python 3, i'd like to run my Python 2.6.1 with Python 3 warning mode.

When i run
python -3

and execute statement
 >>> print 4

then i expect to see a warning because i've understood that this 
statement is not valid in Python 3

however no warning appears.

Have is misunderstood something?
I'm running Python on Windows Vista.

thanks in advance!
Aivar