datetime.datetime(2020, 12, 19, 6, 53, 12, 762350, tzinfo=<UTC>) != '2020-12-19T06:53:12.762350Z' code example

Example: python datetime to string iso format

from datetime import datetime
some_date = datetime.now()
iso_date_string = some_date.isoformat()

# For older version of python 
iso_date_string = some_date.strftime('%Y-%m-%dT%H:%M:%S.%f%z')