def get_signed_purchase_params(cart, callback_url=None, extra_data=None):
 return sign(get_purchase_params(cart, callback_url=callback_url, extra_data=extra_data))

def get_signed_purchase_params ( cart , callback_url = None , extra_data = None ) : return sign ( get_purchase_params ( cart , callback_url = callback_url , extra_data = extra_data ) )
return the parameters to send to the current payment processor .