I have fetched a date from database with the following variable
{{ i.operation_date }}
It seems from your question that you would like to simply increment the year of your given date rather than worry about leap year implications. You can use the date class to do this by accessing its member year.
from datetime import date
startDate = date(2012, 12, 21)
# reconstruct date fully
endDate = date(startDate.year + 1, startDate.month, startDate.day)
# replace year only
endDate = startDate.replace(startDate.year + 1)
If you're having problems creating one given your format, let us know.