Hello, I want to make an if that checks if the user has manager or user rights like this:

if order.user_has_groups('purchase.group_purchase_user') and order.amount_total > 5000:
    raise UserError(_("You can\'t confirm the purchase order, please contact the current purchase manager."))
    return False
if order.user_has_groups('purchase.group_purchase_manager'):

My problem now is that the purchase manager has the user rules too. So It goes everytime to the UserError if. 

How can I fix that, that the user with "purchase: user" rights go to the usererror and the "manager" to the other?

Thank you very much