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