code: def get_all_if_deleted(self):
          
  
          with self._lock:
              results = {}
              for add, fut in self._state.items():
                  if self._contains_and_deleted(add):
                      results[add] = fut.result()
              return results
docs: Return all the addresses deleted in the context.
          Useful in the squash method.
  
          Returns:
              (dict of str to bytes): The addresses and bytes that have
                  been deleted in the context.