<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def addend_ids(self):
 """tuple of int ids of elements contributing to this subtotal. Any element id not present in the dimension or present but representing missing data is excluded. """

        return tuple(
            arg
            for arg in self._subtotal_dict.get("args", [])
            if arg in self.valid_elements.element_ids
        )