human
Solve the following python programming problem given the following code:
def _encode_json(obj) : 
    '
    Encode object as json str.
    ' 
    def _dump_obj(obj) : 
        if isinstance (obj, dict) : 
            return obj 
d = dict () 
        for k in dir (obj) : 
            if (not k.startswith ('_')) : 
                d [k] = getattr (obj, k) 
return d 
return json.dumps (obj, default = obj) 

    
    

    Fix the buggy line: return json.dumps (obj, default = obj)
assistant
#Here is Python code to fix the buggy line: return json.

return json.dumps (obj, default = def _dump_obj()