code: func (t *Collection) Get(key []byte) (val []byte, err error) {
  	i, err := t.GetItem(key, true)
  	if err != nil {
  		return nil, err
  	}
  	if i != nil {
  		return i.Val, nil
  	}
  	return nil, nil
  }
docs: // Retrieve a value by its key.  Returns nil if the item is not in the
  // collection.  The returned value should be treated as immutable.