NameError: name 'timedelta' is not defined

[Benjamin Drung]

Generating the report fails after commit https://git.launchpad.net/ubuntu-sponsoring/commit/?id=a1493abb2b0a95044c36260e18fa7465a60d9bbc:

```
Traceback (most recent call last):
  File "/usr/bin/sponsors-page", line 11, in <module>
    load_entry_point('ubuntu-sponsoring==1.0', 'console_scripts', 'sponsors-page')()
  File "/usr/lib/python3/dist-packages/ubuntu_sponsoring/sponsors_page.py", line 905, in main
    generate_page(
  File "/usr/lib/python3/dist-packages/ubuntu_sponsoring/sponsors_page.py", line 745, in generate_page
    subst["AGEAVERAGE"] = str((sum((x.date_queued for x in items), timedelta()) / len(items)))
NameError: name 'timedelta' is not defined
```

[Benjamin Drung (bdrung)]

It fails now with:

```
$ python3 -m ubuntu_sponsoring.sponsors_page -v
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/home/bdrung/projects/ubuntu-sponsoring/ubuntu_sponsoring/sponsors_page.py", line 929, in <module>
    main()
  File "/home/bdrung/projects/ubuntu-sponsoring/ubuntu_sponsoring/sponsors_page.py", line 906, in main
    generate_page(
  File "/home/bdrung/projects/ubuntu-sponsoring/ubuntu_sponsoring/sponsors_page.py", line 746, in generate_page
    subst["AGEAVERAGE"] = str((sum((x.date_queued for x in items), datetime.timedelta()) / len(items)))
                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: unsupported operand type(s) for +: 'datetime.datetime' and 'datetime.datetime'
```

[Athos Ribeiro (athos-ribeiro)]

Should we re-open this?

[Benjamin Drung (bdrung)]

Commit 7853edd8c6f72229dea35ee59bd0c043e85048f8 fixed the report generation.

[Alex Murray (alexmurray)]

FWIW I created https://code.launchpad.net/~alexmurray/ubuntu-sponsoring/+git/ubuntu-sponsoring/+merge/479717to try and avoid this in the future if anyone is keen to review it?