You are right - they are not milliseconds. I've decided to use the basic_date_time_no_millis
date format like this:
from datetime import datetime
dt = datetime.utcnow()
timestamp = dt.strftime('%Y%m%d')
timestamp += dt.strftime('T%H%M%S')
Which results in a timestamp like 20190817T105422
. That lead to another issue . I guess this format should work with Curator.