- 'created_at': '2014-01-01T01:02:03Z',
- 'modified_at': time.strftime('%Y-%m-%dT%H:%M:%SZ',
- time.gmtime(time.time() - age)),
+ 'created_at': '2014-01-01T01:02:03.04050607Z',
+ 'modified_at': mod_time_s,
+ 'first_ping_at': kwargs.pop('first_ping_at', mod_time_s),
+ 'last_ping_at': mod_time_s,