The wizard we are presenting requires the user to fill in the name of the member in the form. There is a feature of the web client we can use to save some typing. When an action is executed, the context is updated with some values that can be used by wizards:

These values can be used to compute default values of the model, or even directly in the method called by the button. To improve on the recipe example, if we had a button displayed on the form view of a library.member model to launch the wizard, then the context of the creation of the wizard would contain {'active_model': 'library.member', 'active_id': <member id>}. In that case, you could define the member_id field to have a default value computed by the following method:

def _default_member(self):
    if self.context.get('active_model') == 'library.member':
        return self.context.get('active_id', False)

In step 2, we could have dispensed with the for wizard in self loop, and assumed that len(self) is 1, possibly adding a call to self.ensure_one() at the beginning of the method, like this:

@api.multi
def record_borrows(self):
    self.ensure_one()
    member = self.member_id
    books = self.book_ids
    member.borrow_books(books)

We recommend using the version in the recipe though, because it allows reusing the wizard from other parts of the code by creating records for the wizard, putting them in a single recordset (see the Combine recordsets recipe in Chapter 5, Basic Server Side Development, to see how to do this) and then calling record_loans() on the recordset. Granted, here the code is trivial and you don't really need to jump through all those hoops to record that some books were borrowed by different members. However, in an Odoo instance, some operations are much more complex, and it is always nice to have a wizard available that does "the right thing." When using such wizards, be sure to check the source code for any possible use of the active_model / active_id / active_ids keys from the context, in which case, you need to pass a custom context (see the Call a method with a modified context recipe previously for how to do this).

The method in step 2 does not return anything. This will cause the wizard dialog to be closed after the action is performed. Another possibility is to have the method return a dictionary with the fields of an ir.action. In this case, the web client will process the action as if a menu entry had been clicked on by the user. For instance, if we wanted to display the form view of the member who has just borrowed the books, we could have written the following:

    @api.multi
    def record_borrows(self):
        for wizard in self:
            member = wizard.member_id
            books = wizard.book_ids
            member.borrow_books(books)
        member_ids = self.mapped('member_id').ids
        action = {
            'type': 'ir.action.act_window',
            'name': 'Borrower',
            'res_model': 'library.member',
            'domain': [('id', '=', member_ids)],
            'view_mode': 'form,tree',
        }
        return action

This builds a list of members who has borrowed books from this wizard (in practice, there will only be one such member, when the wizard is called from the user interface) and creates a dynamic action, which displays the members with the specified IDs.

This trick can be extended by having a wizard (with several steps to be performed one after the other), or depending on some condition from the preceding steps, by providing a Next button that calls a method defined on the wizard. This method will perform the step (maybe using a hidden field and storing the current step number), update some fields on the wizard, and return an action that will redisplay the same updated wizard and get ready for the next step.