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

sale.py

@@ -1,5 +1,6 @@
 from trytond.pool import Pool, PoolMeta
 from trytond.model import ModelView, ModelSQL, fields
+from trytond.pyson import Eval, Bool, If
 
 
 class SaleLine(metaclass=PoolMeta):
@@ -19,3 +20,11 @@ class SaleLine(metaclass=PoolMeta):
         cls._process_invoice_shipment_states(sales)
         cls._process_state(sales)
 
+    @classmethod
+    def view_attributes(cls):
+        return super(SaleLine, cls).view_attributes() + [
+            ('//page[@id="equipment"]', 'states', {
+                    'invisible': ~Eval('lines.product.equipment'),
+                    })]
+
+