How to make all the 'inlines' collapsible items in Django Admin to default open?

Question

I am new to Django and Python programming and I have looking in circles to solve this problem I have. I wrote following codes...whenever the below codes were executed, the inline filter is always default as 'close'. How can I default to 'open' or 'show' instead of default 'close'? Thank you.

class ArInvoiceSimpleInlineForeign(admin.TabularInline):
    model = ArInvoice
    extra = 2
    classes = ('collapse open',)
    inline_classes = ('collapse open',)