How to increment date by week?

[steve.ferg.bitbucket at gmail.com]

pyfdate -- http://www.ferg.org/pyfdate/

from pyfdate import Time 
w = Time(2013,1,2) # start with January 2, 2013, just for example

# print the ISO weeknumber and date for 52 weeks
# date looks like this: October 31, 2005
for i in range(52):
    w = w.plus(weeks=1)
    print (w.weeknumber, w.d)