code: def _serialize_default(cls, obj):
          
  
          if obj is None or cls._is_primitive(obj):
              return obj
          elif cls._is_bytes(obj):
              return obj.decode()
          elif type(obj) == list:
              return cls._serialize_list(obj)
          else:
              dict_ = cls._get_obj_raw(obj)
  
              return cls._serialize_dict(dict_)
docs: :type obj: int|str|bool|float|bytes|unicode|list|dict|object
  
          :rtype: int|str|bool|list|dict