now = datetime.datetime.now()
# 2017-04-10T00%3A00%3A00
print now
r = requests.get('.....&start__gte=2017-04-10T00%3A00%3A00')
response = r.json()
print response["objects"][0]["href"]
>>> import datetime
>>> now = datetime.datetime.now()
>>> now
datetime.datetime(2017, 4, 11, 11, 40, 51, 361335)
>>> now.isoformat()
'2017-04-11T11:40:51.361335'
>>> import urllib
>>> urllib.urlencode({'start_gte': now.isoformat()})
'start_gte=2017-04-11T11%3A40%3A51.361335'