在python中使用business_calendar时的警告信息

Question

I would like to use the business_calendar function in python. I have a list of public holidays I would like to add to my calendar. I have followed the example code in creating my calendar, here is my code:

from business_calendar import Calendar, MO, TU, WE, TH, FR
import datetime
date1 = datetime.datetime(2017,9,22)
cal = Calendar(holidays=list([datetime.datetime(2017,9,25),datetime.datetime(2017,9,28)]))
date2 = (cal.addbusdays(date1, 3))
print (date2)

The function seems to be working correctly, however I am concerned about the warning message that is displayed:

C:\Program Files\WinPython-64bit-3.5.2.3\python-3.5.2.amd64\lib\site-packages\spyder\utils\ipython\start_kernel.py:5: CalendarHolidayWarning: Holiday list exhausted at end, addbusday(2017-09-22 00:00:00,3) output may be incorrect. # (see spyder/__init__.py for details)

I have attempted to find out how to resolve this, but have had no luck. Any assistance would be appreciated.

Thank you

Answer 1

It's giving you this warning because it has reached the last holiday in your list, and has no way of knowing how far into the future that list covers. Specifically, it has no way of knowing whether the 29th is a holiday or not. Adding a holiday far in the future, or having the whole year's holidays in the list (which is probably the normal use-case for this module), would avoid the warning.

Answer 2

In case someone is wondering. The list may be exahusted because the remaining holidays are in a non-working days. So basically you can add few artificial holidays on 29,30,31.12 or around asian new year, if this is the case :) Or you may just ignore the message.