code: func Get(overseer Overseer, w http.ResponseWriter, r *http.Request, key string) (string, error) {
  	val, err := overseer.Get(w, r)
  	if err != nil {
  		return "", errors.Wrap(err, "unable to get session")
  	}
  
  	var sess session
  	err = json.Unmarshal([]byte(val), &sess)
  	if err != nil {
  		return "", errors.Wrap(err, "unable to unmarshal session object")
  	}
  
  	var sessMap map[string]string
  	err = json.Unmarshal(*sess.Value, &sessMap)
  	if err != nil {
  		return "", errors.Wrap(err, "unable to unmarshal session map value")
  	}
  
  	mapVal, ok := sessMap[key]
  	if !ok {
  		return "", errNoMapKey{}
  	}
  
  	return mapVal, nil
  }
docs: // Get is a JSON helper used for retrieving key-value session values.
  // Get returns the value pointed to by the key of the marshalled map stored in the session.