Misleading/incorrect error message when using invalid `AP_API_BASE_URL`

[mileswwatkins]

Just hit this for a while when setting up an app that depends on Elex, but where I'd injected an invalid AP_API_BASE_URL:

It ran: elex results --national-only --results-level ru --set-zero-counts 2016-11-08 > .data/results.csv (with an invalid AP_API_BASE_URL in os.environ)

And got in response: 2016-11-08 could not be recognized as a date.

This message is produced by the @require_date_argument decorator, presumably when it fails to find a date in the API's response.

elex/elex/cli/decorators.py

Lines 19 to 27 in 6efd08a

	try:
	self.app.election.electiondate = parse_date(
	self.app.pargs.date[0]
	)
	return fn(self)
	except ValueError:
	text = '{0} could not be recognized as a date.'
	self.app.log.error(text.format(self.app.pargs.date[0]))
	self.app.close(1)

This error message is misleading and frustrating; 2016-11-08 can indeed correctly get parsed by dateutil, and the error instead is that the field couldn't be found in the first place, I believe.