code: func (q *WrapperQuery) Source() (interface{}, error) {
  	// {"wrapper":{"query":"..."}}
  	source := make(map[string]interface{})
  	tq := make(map[string]interface{})
  	source["wrapper"] = tq
  	tq["query"] = q.source
  	return source, nil
  }
docs: // Source returns JSON for the query.