Remove docs for resource.

        :param resource: resource name
        :param lookup: filter
        :param parent: parent id

def remove(self, resource, lookup=None, parent=None, **kwargs):
        """Remove docs for resource.

        :param resource: resource name
        :param lookup: filter
        :param parent: parent id
        """
        kwargs.update(self._es_args(resource))
        if parent:
            kwargs['parent'] = parent

        if lookup:
            if lookup.get('_id'):
                try:
                    return self.elastic(resource).delete(id=lookup.get('_id'), refresh=True, **kwargs)
                except elasticsearch.NotFoundError:
                    return
        return ValueError('there must be `lookup._id` specified')