Python class attributes from/to dictionary

class McItems(dict):

    attrs = ["guid"]

    def as_dict(self):
        return self.__dict__

    def from_dict(self, *val, **kwargs):
        for key in val:
            setattr(self, key, val[key])
        for key in kwargs:
            setattr(self, key, kwargs[key])

    def from_dict_selected(self, *val, **kwargs):
        if len(self.attrs) == 1:
            raise "overwrite for McItems has to have attrs with list of more than one item"

        for key in val:
            if key in val.attrs:
                setattr(self, key, val[key])