code: func (mc MongoClient) IntervalByName(name string) (contract.Interval, error) {
  	s := mc.getSessionCopy()
  	defer s.Close()
  
  	query := bson.M{"name": name}
  
  	mi := models.Interval{}
  	if err := s.DB(mc.database.Name).C(db.Interval).Find(query).One(&mi); err != nil {
  		return contract.Interval{}, errorMap(err)
  	}
  	return mi.ToContract(), nil
  }
docs: // Return an Interval by name
  // UnexpectedError - failed to retrieve interval from the database