tab 'equipment invisible in line of purchase when product is 'equipment'

purchase.py

@@ -62,7 +62,39 @@ class Line(metaclass=PoolMeta):
     address_equipment = fields.Many2One('party.address', "Direccion", required=True)
     serial_equipment = fields.Char("Serial", size=None, required=True)
     refurbish = fields.Boolean("Refurbish")
-    
+    product_equipment = fields.Boolean("Product Equipment")
+
+    def on_change_product(self):
+        if not self.product:
+            self.product_equipment = False
+            return
+
+        party = None
+        if self.purchase:
+            party = self.purchase.invoice_party or self.purchase.party
+
+        # Set taxes before unit_price to have taxes in context of purchase
+        # price
+        self.taxes = self.compute_taxes(party)
+
+        category = self.product.purchase_uom.category
+        if not self.unit or self.unit.category != category:
+            self.unit = self.product.purchase_uom
+
+        product_suppliers = list(self.product.product_suppliers_used(
+                **self._get_product_supplier_pattern()))
+        if len(product_suppliers) == 1:
+            self.product_supplier, = product_suppliers
+        elif (self.product_supplier
+                and self.product_supplier not in product_suppliers):
+            self.product_supplier = None
+
+        self.unit_price = self.compute_unit_price()
+
+        self.type = 'line'
+        self.amount = self.on_change_with_amount()
+        self.product_equipment = True
+
     def default_address_equipment():
         pool = Pool()
         Company = pool.get('company.company')
@@ -70,13 +102,10 @@ class Line(metaclass=PoolMeta):
         if company:
             company = Company(company)
             return company.party.addresses[0].id
-        
+
-    """
     @classmethod
     def view_attributes(cls):
         return super(Line, cls).view_attributes() + [
             ('//page[@id="equipment"]', 'states', {
-                    'invisible': Eval('product.equipment'),
+                    'invisible': ~Eval('product_equipment', True),
                     })]
-    """
-    

view/purchase_line_form.xml

@@ -14,4 +14,9 @@
 	    <field name="refurbish"/>
 	</page>
     </xpath>
+    <xpath
+        expr="/form/notebook/page[@id='general']/field[@name='product']" position="after">
+        <label name="product_equipment"/>
+        <field name="product_equipment"/>
+    </xpath>
 </data>