i'm trying to format the date like this,

2015-12-02T12:57:17+00:00

here's my code

```
time.strftime("%Y-%m-%dT%H:%M:%S%z", time.gmtime())

```

which gives this result,

2015-12-02T12:57:17+0000

i can't see any other variations of %z that can provide the correct format of +00:00 ? what's the correct way to go about this?