fask-RESTful Api return Internal Server Error

{"message": "Internal Server Error"}
`</pre>

Json structures support contain dict,array,value([http://www.json.org/json-zh.html](http://www.json.org/json-zh.html)).

if your json structures contain other ,you need use `str()` function to type conversion.

<pre>`articles = Article.objects.all()
alist = dict()
for one in articles:
    myComments = dict()
    if one.comments is None:
        myComments = {}
    else:
        for comment in one.comments:
            myComments = {
                'created_at': str(comment.created_at),
                'body': str(comment.body),
                'author' : str(comment.author),
            }
    json_dict = {
        'created_at' : str(one.created_at),
        'title' : one.title,
        'slug' : one.slug,
        'body' : str(one.body),
        'comments' : myComments
    }
    alist.setdefault(one.slug, json_dict)