TypeError: Object of type TextIOWrapper is not JSON serializable

I had this error and I used the json.dump the wrong way around:

Correct way:

with open("Jello.json", "w") as json_file:
    json.dump(object_to_be_saved, json_file)

Wrong way:

I did it the other way around json.dump(json_file, object_to_be_saved)… Thanks Python.