Initialize a Content object from a json dictionary.

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