hi, please help me i cannot figure out why is not working,

in the sale order view, i want avoid a user add more product when the order is delivered or invoiced, i do the xml to replace the attrib of the the control and make invisible the add product button

i have the next:

    {'invisible': [('invoice_status', 'in', ('to invoice','invoiced'))]}

the view has the next 

...

why im wrong?

thanks