@classmethod
def get(cls, id, using=None, index=None, **kwargs):
    """
        Retrieve a single document from elasticsearch using its ``id``.

        :arg id: ``id`` of the document to be retrieved
        :arg index: elasticsearch index to use, if the ``Document`` is
            associated with an index this can be omitted.
        :arg using: connection alias to use, defaults to ``'default'``

        Any additional keyword arguments will be passed to
        ``Elasticsearch.get`` unchanged.
        """
    es = cls._get_connection(using)
    doc = es.get(index=cls._default_index(index), id=id, **kwargs)
    if not doc.get('found', False):
        return None
    return cls.from_es(doc)
