Forms shouldn't require whole Payment object instance about django-payments

[patrys]

This is not trivial.

Some payment gateways require the form to be cryptographically signed using a hidden input. You need a payment object to do this.

Some payment gateways require that the form's action points to an external server. You can't put these inside a single page checkout.

get_form() is really a view. It either returns a form to display or tells you to redirect the user somewhere. It was not meant to be composed with other such views as there is no way to redirect a single browser to two separate resources. If you really want to call get_form() from a composite view, do not pass in data unless all other forms are valid and you've already saved them (so that get_form() can save whatever it wants and take over).