:date: 2016-04-27

=========================
Wednesday, April 27, 2016
=========================

Alexa wants to print a list of the participants of a continous course,
together with "invoicing info" and "payment info".

Excerpts can now be certifying even on a model which is not
Certifiable. In that case you don't have a `printed` field on the
owner, but Lino creates at most one excerpt per database object.

The filename of a certifying non-primary excerpt is
`courses.Course.12-34.pdf` (where `12` is the ID of the excerpt type
and `34` the ID of the course).



:class:`EnrolmentsAndPaymentsByCourse
<lino_voga.lib.courses.models.EnrolmentsAndPaymentsByCourse>`



>>> from decimal import Decimal
>>> Decimal('45.00') * '1'
Traceback (most recent call last):
...
TypeError: can't multiply sequence by non-int of type 'Decimal'