code: func SolrErrorResponse(m map[string]interface{}) (bool, *ErrorResponse) {
  	// check for existance of "error" key
  	if _, found := m["error"]; found {
  		error := m["error"].(map[string]interface{})
  		return true, &ErrorResponse{
  			Message: error["msg"].(string),
  			Status:  int(error["code"].(float64)),
  		}
  	}
  	return false, nil
  }
docs: /*
   * Determines whether a decoded response from Solr
   * is an error response or not. Returns a bool (true if error)
   * and an ErrorResponse (if the response is an error response)
   * otherwise nil
   */