Question

i know using datetime.timedelta i can get the date of some days away form given date

daysafter = datetime.date.today() + datetime.timedelta(days=5)

but seems no datetime.timedelta(month=1)

Answer 1

Of course there isn’t — if today’s January 31, what would be “the same day of the next month”?! Obviously there is no right solution, since February 31 does not exist, and the datetime module does not play at “guess what the user posing this impossible problem without a right solution thinks (wrongly) is the obvious solution”;-).

I suggest:

try:
  nextmonthdate = x.replace(month=x.month+1)
except ValueError:
  if x.month == 12:
    nextmonthdate = x.replace(year=x.year+1, month=1)
  else:
    # next month is too short to have "same date"
    # pick your own heuristic, or re-raise the exception:
    raise