tab 'equipment' in purchase invisible if product not is a equipment

purchase.py

@@ -51,71 +51,11 @@ class Purchase(metaclass=PoolMeta):
             purchase.equipment_available = True
             cls.save(purchases)
             #raise UserError(str(purchase.equipment_available))
-
         else:
             raise InvalidNumberPurchases(
                 gettext('purchase.msg_invalid_number_purchases'))
 
             
-
-            
-    """
-    @classmethod
-    @ModelView.button
-    def process(cls, purchases):
-        pool = Pool()
-        Equipment = pool.get('optical_equipment.equipment')
-        #raise UserError(str(type(Equipment)))
-        Line = pool.get('purchase.line')
-        lines = []
-        process, done = [], []
-        cls.lock(purchases)
-        for purchase in purchases:
-            if purchase.state not in {'confirmed', 'processing', 'done'}:
-                continue
-            purchase.create_invoice()
-            purchase.set_invoice_state()
-            purchase.create_move('in')
-            return_moves = purchase.create_move('return')
-            if return_moves:
-                purchase.create_return_shipment(return_moves)
-            purchase.set_shipment_state()
-            #raise UserError(str(dir(purchase)))
-            #equipment = Equipment() 
-            for line in purchase.lines:
-                #raise UserError(str(dir(line)))
-                equipment = Equipment(
-                    company=line.company,
-                    equipment_type=line.product.equipment_type,
-                    party_address=line.address_equipment,
-                    product=line.product,
-                    risk=line.product.risk,
-                    use=line.product.use,
-                    biomedical_class=line.product.biomedical_class,
-                    calibration=line.product.calibration,
-                    refurbish=line.refurbish,
-                    serial=line.serial_equipment,
-                    software_version=line.product.software_version,
-                )
-                equipment.save()
-                #raise UserError(str([equipment.serial, equipment.software_version]))
-                line.set_actual_quantity()
-                lines.append(line)
-                
-            if purchase.is_done():
-                if purchase.state != 'done':
-                    if purchase.state == 'confirmed':
-                        process.append(purchase)
-                    done.append(purchase)
-            elif purchase.state != 'processing':
-                process.append(purchase)
-        Line.save(lines)
-        if process:
-            cls.proceed(process)
-        if done:
-            cls.do(done)
-        """
-            
 class Line(metaclass=PoolMeta):
     __name__ = 'purchase.line'
 
@@ -123,3 +63,10 @@ class Line(metaclass=PoolMeta):
     serial_equipment = fields.Char("Serial", size=None, required=True)
     refurbish = fields.Boolean("Refurbish")
 
+    @classmethod
+    def view_attributes(cls):
+        return super(Line, cls).view_attributes() + [
+            ('//page[@id="equipment"]', 'states', {
+                    'invisible': ~Eval('line.product.equipment'),
+                    })]
+