Python : consolidate 0

I am using Python to cut my offline and set the shot name from a CSV
I would like to assign as well my frame number to 1011 for the first frame of my new cut segment.
I can’t use segment.change_start_frame(1011) if the head is more than 1011 (flame refuse the possibility to have negative number).
I need to consolidate my segment but I can’t figure out how to do it in python

Any Clue ?