I am trying to compare the current date and time with dates and times specified in models using comparison operators:
if challenge.datetime_start <= datet
Disable time zone. Use challenge.datetime_start.replace(tzinfo=None);
challenge.datetime_start.replace(tzinfo=None);
You can also use replace(tzinfo=None) for other datetime.
replace(tzinfo=None)
if challenge.datetime_start.replace(tzinfo=None) <= datetime.now().replace(tzinfo=None) <= challenge.datetime_end.replace(tzinfo=None):