How to generate a random datetime interval in python?

I need to generate a random pair of dates as a time interval in python

Like from January 1 to June 2 2017 or from May 4 to September 9 2018

I'm using this to generate a random date:

now = firstJan + timedelta(days = random.randint(0, 365 if calendar.isleap(firstJan.year) else 364))

How do I generate a random interval?