I think in this case (due to how long the lines are and the level of indention at this point) would have preferred to simply move the first argument down to be with the rest (see below). As Mike pointed out this is also pep8 approved.

    data = db.view(
        'hsph/facility_registrations',
        startkey=key + [self.datespan.startdate_param_utc],
        endkey=key + [self.datespan.enddate_param_utc],
        reduce=True,
        wrapper=lambda r: r['value']
    ).first()