This factory for :class:`Model`
        takes either a native Python dictionary or a JSON dictionary/object
        if ``is_json`` is ``True``. The dictionary passed does not need to
        contain all of the values that the Model declares.

def from_dict(cls, D, is_json=False):
        '''This factory for :class:`Model`
        takes either a native Python dictionary or a JSON dictionary/object
        if ``is_json`` is ``True``. The dictionary passed does not need to
        contain all of the values that the Model declares.

        '''
        instance = cls()
        instance.set_data(D, is_json=is_json)
        return instance