Make a navigation request on the DTS API

        :param collection_id: Id of the collection
        :param ref: If ref is a tuple, it is treated as a range. String or int are treated as single ref
        :param mimetype: Media type to request
        :return: Response
        :rtype: requests.Response

def get_document(
            self,
            collection_id, ref=None, mimetype="application/tei+xml, application/xml"):
        """ Make a navigation request on the DTS API

        :param collection_id: Id of the collection
        :param ref: If ref is a tuple, it is treated as a range. String or int are treated as single ref
        :param mimetype: Media type to request
        :return: Response
        :rtype: requests.Response
        """
        parameters = {
            "id": collection_id
        }
        _parse_ref_parameters(parameters, ref)

        return self.call(
            "documents",
            parameters,
            mimetype=mimetype
        )