m_days.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

for y in (2011, 2012, 2100, 2400):

    print 'year:', y

    for m in range(1, 12+1):
        m_days = 30 + (m+(m>=8))%2 - 2*(m==2) + (m==2 and (not y%4 and not not y%100 or not y%400))
        print m, m_days

    print

# output:
#    year: 2011
#    1 31
#    2 28
#    3 31
#    4 30
#    5 31
#    6 30
#    7 31
#    8 31
#    9 30
#    10 31
#    11 30
#    12 31
#    
#    year: 2012
#    1 31
#    2 29
#    3 31
#    4 30
#    5 31
#    6 30
#    7 31
#    8 31
#    9 30
#    10 31
#    11 30
#    12 31
#    
#    year: 2100
#    1 31
#    2 28
#    3 31
#    4 30
#    5 31
#    6 30
#    7 31
#    8 31
#    9 30
#    10 31
#    11 30
#    12 31
#    
#    year: 2400
#    1 31
#    2 29
#    3 31
#    4 30
#    5 31
#    6 30
#    7 31
#    8 31
#    9 30
#    10 31
#    11 30
#    12 31