code: public AVQuery<T> whereDoesNotMatchKeyInQuery(String key, String keyInQuery, AVQuery<?> query) {
      Map<String, Object> map = AVUtils.createMap("className", query.className);
      map.put("where", query.conditions.compileWhereOperationMap());
  
      Map<String, Object> queryMap = AVUtils.createMap("query", map);
      queryMap.put("key", keyInQuery);
  
      addWhereItem(key, "$dontSelect", queryMap);
      return this;
    }
docs: Add a constraint to the query that requires a particular key's value does not match any value
  for a key in the results of another AVQuery.
  
  @param key The key whose value is being checked and excluded
  @param keyInQuery The key in the objects from the sub query to look in
  @param query The sub query to run
  @return Returns the query so you can chain this call.