Is there a datetime ± infinity?

Try this:

>>> import datetime
>>> datetime.datetime.max
datetime.datetime(9999, 12, 31, 23, 59, 59, 999999)

You can get min/max for datetime, date, and time.

There isn't; the best you have is the datetime.datetime.min and datetime.datetime.max values.

These are guaranteed to be the smallest and largest datetime values, but datetime.datetime.min == datetime.datetime.min is still True; everything else is larger. The inverse is true for the datatime.datetime.max value.

There are also min and max values for datetime.date and datetime.time.