How to use on_duplicate_ignore with subselect?

In PostgreSQL, when attempting to do something like the following:

customers, customers_backup = Tables('customers', 'customers_backup')

q = Query.into(customers_backup).columns('id', 'fname', 'lname')
    .from_(customers).select(customers.id, customers.fname, customers.lname).on_duplicate_ignore()

I get the error TypeError: 'Field' object is not callable. Am I doing something wrong or is this not yet supported?

[ivanvenosdel]

Great! I will try it out and get back to you.

[airtonzanon]

Indeed, on MySQL it works:

q = MySQLQuery.into(customers_backup).columns('id', 'fname', 'lname'). \
from_(customers).select(customers.id, customers.fname, customers.lname).on_duplicate_key_ignore()

output:

INSERT INTO `customers_backup` (`id`,`fname`,`lname`) SELECT `id`,`fname`,`lname` FROM `customers` ON DUPLICATE KEY IGNORE

This is not implemented for PostgreSQL dialect. What would be the right output for PostgreSQL? With the right output I can take a look and implement that for PostgreSQL as well.