# Wednesday, January 28, 2015¶

Yesterday’s work on #80 (Convert Partner to Person) made be think about The lino.utils.mti.EnableChild field. This field is not really user-friendly. Can’t I write something equivalent using action buttons? A “Polymorphy manager” field. Or should it be integrated with the polymorphy navigator?

Result: cool! Lino’s MTI navigator now includes buttons for adding and deleting MTI children.

## Getting the Lino docs to build¶

I removed the requirement of sphinxcontrib.taglist since that module is no longer maintained.

## More about VAT¶

Congratulations to Mahmoud who contributed his first pull request.

We then discovered that there are still armies of bugs sitting in the lino.modlib.vat djungle. And I get the feeling that this is indeed a job for me. I need to do some more work on this, otherwise nobody has any chance to understand anything.

• Renamed VatRate to VatRule. I plan to move the fields purchases_vat_account and sales_vat_account (which are currently in system.SiteConfig) to this model as well. Because probably there will be users who want Lino to book vat amounts into different accounts for different countries.
• Renamed VatRate.find_vat_rate() to VatRule.get_vat_rule(). It now returns the database object, not just the value of the VatRule.rate field. And there must be exactly one row, it now raises a warning instead of returning ZERO.

Commit at 18.00 : above changes caused Lino Così to fail for the moment. But at least for Lino it should now be possible to build the docs:

$go lino$ fab initdb test bd


Commit at 23.40 : lots of changes. purchase and sales invoices seem to work now. demo_bookings no longer generates bank statements because these seem to not work yet.