def create_membership_invoice(self, cr, uid, ids, product_id=None, datas=None, context=None):
# NOTE: use context to supply date_from to account_invoice_line.create
def create_membership_invoice(self, cr, uid, ids, product_id=None, datas=None, context=None):
# NOTE: use context to supply date_from to account_invoice_line.create