The parser from dateutil is your friend.
You’ll have to pip install dateutil but you’ve save bags and bags of date conversion code:
pip install python-dateutil
You can use it like this.
from dateutil import parser
ds="2012-03-01T10:00:00Z" # or any date sting of differing formats.
date = parser.parse(ds)
You’ll find you can deal with almost any date string formats with this parser and you’ll get a nice standard python date back