[1.7.x] Fixed #23296 -- Fixed RunPython code sample in Migration Operations.
[1.7.x] Fixed #23296 -- Fixed RunPython code sample in Migration Operations.

Backport of 7ca665c5f5 from master

jyotsna1820/django,jyotsna1820/django,oscaro/django,oscaro/django,oscaro/django,oscaro/django,jyotsna1820/django,jyotsna1820/django