Fill in the blank using mapper to convert JSON string into an instance of the Post class.
ObjectMapper mapper = new ObjectMapper();
String postJson = "{\"id\":1,\"createdDate\":1655112861424,\"content\":\"I learned how to use jackson!\",\"likes\":10,\"comments\":[\"Well done!\",\"Great job!\"]}";
Post post = _________________; // Fill in this blank
Do not include a ;.