code: func (dict Dictionary) Contains(word string) bool {
  	if dict.root == nil {
  		return false
  	}
  	targetNode := dict.root.Navigate(word)
  	return targetNode != nil && targetNode.IsWord
  }
docs: // Contains searches the Dictionary to see if the specified word is present.
  //
  // Time complexity: O(m) where 'm' is the length of word.