================================
20130716 (Tuesday, 16 July 2013)
================================

Expected a string, got 30L
--------------------------

When trying the :class:`Create 
Invoice <lino.modlib.auto.sales.models.CreateInvoiceForPartner>`
action to :class:`faggio.sales.InvoiceablePartners`
on 
`faggio-demo <http://faggio-demo.lino-framework.org/>`_
I got the above traceback.
This was because Lino's 
:meth:`QuantityField.to_python <lino.core.fields.QuantityField.to_python>`
implementation wasn't yet robust enough.
Here some test cases:

>>> from decimal import Decimal
>>> from lino import startup
>>> startup('lino_book.projects.min1.settings')
>>> from lino.api import dd
>>> f = dd.QuantityField()
>>> f.to_python(None)
>>> f.to_python(30)
Decimal('30')
>>> # f.to_python(30L) no longer valid in python 3
Decimal('30')
>>> print(f.to_python(''))
None
>>> f.to_python(Decimal(0))
Decimal('0')

Events, Guests and Clients
--------------------------

I found a way for making workflows configurable.
See 

I replaced the `fill_event_guests_from_team_members` function 
(a receiver for the `post_save` signal on `Event`) by
two methods 
:meth:`lino_xl.lib.cal.Event.add_guests`
and
:meth:`lino_xl.lib.cal.Event.suggest_guests`.
Which shows that 
I prefer subclassing over signals 
for making these things customizable.


Then I applied the new ideas for inheriting apps to lino_welfare: 
New modules 
:mod:`lino_welfare.modlib.cal`,
:mod:`lino_welfare.modlib.contacts`
and
:mod:`lino_welfare.modlib.ui`


Aha! And here is also another missing piece: 
:attr:`lino.ad.app.extends_models` instead of having 
to specify them in 
:attr:`lino.ui.Site.override_modlib_models`.


Checkin.

TODO: some tests are failing 
because `lino.ui` is no longer automatically being yeld by 
get_installed_plugins.