[web2py] crud onaccept vs form.accepts - is this expected

[selecta]

def edit():
    record_id = request.args(0)
    def on_accept(form):
        print 'in on accept'
        response.headers['web2py-component-command'] =
XML("web2py_component('%s','list')"%URL('list'))
    if not record_id:
        db.plugin_whishlist.open.readable,
db.plugin_whishlist.open.writable = False, False
        form = crud.create(db.plugin_whishlist, onaccept = on_accept)
    else:
            form = crud.update(db.plugin_whishlist, record_id,
onaccept = on_accept)
    if form.accepts(request.vars, session):
            print 'in this on accept ', form.vars.id
            response.headers['web2py-component-command'] =
XML("web2py_component('%s','list')"%URL('list'))
            return ''
    return form

if the form is accepted it will print
"in this on accept" that means it uses form.accepts instead of the
function that is passed.
is this behavior expected? it confused me a bit