code: func (mc MongoClient) getRegistration(q bson.M) (models.Registration, error) {
  	s := mc.getSessionCopy()
  	defer s.Close()
  
  	var reg models.Registration
  	err := s.DB(mc.database.Name).C(db.ExportCollection).Find(q).One(&reg)
  	if err != nil {
  		return models.Registration{}, errorMap(err)
  	}
  	return reg, nil
  }
docs: // Get a single registration for the passed query