Integer, Numeric and Float allow None as value

NULL value is None and not False

issue2022
review237004

tests/scenario_account_stock_continental.rst

@@ -147,6 +147,7 @@ Create product::
     >>> product.list_price = Decimal('10')
     >>> product.cost_price = Decimal('5')
     >>> product.cost_price_method = 'fixed'
+    >>> product.delivery_time = 0
     >>> product.account_expense = expense
     >>> product.account_revenue = revenue
     >>> product.account_stock = stock
@@ -163,7 +164,7 @@ Create payment term::
     >>> PaymentTerm = Model.get('account.invoice.payment_term')
     >>> PaymentTermLine = Model.get('account.invoice.payment_term.line')
     >>> payment_term = PaymentTerm(name='Direct')
-    >>> payment_term_line = PaymentTermLine(type='remainder')
+    >>> payment_term_line = PaymentTermLine(type='remainder', days=0)
     >>> payment_term.lines.append(payment_term_line)
     >>> payment_term.save()