Initialize a Words object from a json dictionary.

def _from_dict(cls, _dict):
        """Initialize a Words object from a json dictionary."""
        args = {}
        if 'words' in _dict:
            args['words'] = [Word._from_dict(x) for x in (_dict.get('words'))]
        else:
            raise ValueError(
                'Required property \'words\' not present in Words JSON')
        return cls(**args)