code: def symmetric_difference_update(self, other):
  		
  		other = setlist(other)
  		indices_to_delete = set()
  		for i, item in enumerate(self):
  			if item in other:
  				indices_to_delete.add(i)
  		for item in other:
  			self.add(item)
  		self._delete_values_by_index(indices_to_delete)
docs: Update self to include only the symmetric difference with other.