ValueError: list.remove(x): x not in list

[luigi]

How to Reproduce

While doing a GET operation on /pdashboard, Trac issued an internal error.

(please provide additional details here)

Request parameters:

{'imagename': None}

System Information

Trac	0.11dev-r5887
Python	2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32 bit (Intel)]
setuptools	0.6c6
SQLite	3.3.4
pysqlite	2.3.2
Genshi	0.4.3
Pygments	0.8.1

Python Traceback

Traceback (most recent call last):
  File "c:\python25\lib\site-packages\Trac-0.11dev_r5887-py2.5.egg\trac\web\main.py", line 406, in dispatch_request
    dispatcher.dispatch(req)
  File "c:\python25\lib\site-packages\Trac-0.11dev_r5887-py2.5.egg\trac\web\main.py", line 216, in dispatch
    resp = chosen_handler.process_request(req)
  File "build\bdist.win32\egg\tracmetrixplugin\web_ui.py", line 119, in process_request
    return self._render_view(req, db)
  File "build\bdist.win32\egg\tracmetrixplugin\web_ui.py", line 192, in _render_view
    backlog_history = tkt_group_metrics.get_daily_backlog_history(first_day, last_day)
  File "build\bdist.win32\egg\tracmetrixplugin\model.py", line 419, in get_daily_backlog_history