code: func (c *Client) Readings() (readings []contract.Reading, err error) {
  	conn := c.Pool.Get()
  	defer conn.Close()
  
  	objects, err := getObjectsByRange(conn, db.ReadingsCollection, 0, -1)
  	if err != nil {
  		return readings, err
  	}
  
  	readings = make([]contract.Reading, len(objects))
  	for i, in := range objects {
  		err = unmarshalObject(in, &readings[i])
  		if err != nil {
  			return readings, err
  		}
  	}
  
  	return readings, nil
  }
docs: // ********************* READING FUNCTIONS *************************
  // Return a list of readings sorted by reading id