month_separation.py

from dateutil.parser import parse
from datetime import timedelta
#
firstdate= parse('2010-04-01')
lastdate = parse('2016-04-02')

start = firstdate
end = min(firstdate+timedelta(months = 1),lastdate)

main(start, end)

while end < lastdate:
    print('start =')
    print (start)
    print ('end = ')
    print(end)
    start = start +timedelta(months = 1)
    end = min(end + timedelta(months=1), lastdate)