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Tuesday, January 6, 2015
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Started to work on :ticket:`51` (Send email notification on update):
We want to send email to a configurable list of addresses when one of
the following fields of a
:class:`lino_welfare.modlib.pcsw.models.Client` have been modified:
first_name, last_name, national_id, primary address, bank account
number.

This has nothing to do with :mod:`lino.modlib.changes`, except that it
is a second use case for the 
:attr:`on_ui_created <lino.core.signals.on_ui_created>`, 
:attr:`on_ui_updated <lino.core.signals.on_ui_updated>` and
:attr:`pre_ui_delete <lino.core.signals.pre_ui_delete>` 
signals. It must be implemented by
writing a receiver for that signal.

Renamed `pre_ui_create` to `on_ui_created` and `pre_ui_update` to
`on_ui_updated` because they are sent when `save()` has been called.

I moved class :class:`ChangeWatcher <lino.core.utils.ChangeWatcher>`
from :mod:`lino.core.dbutils` to :mod:`lino.core.utils`.

And :mod:`lino.dd` no longer includes a shortcut to this class because
it has nothing to do with data definition.

Continued tomorrow.