tokens: Hi all this is my first question here , I 'm very new to Haskell and I need to do a Haskell function which takes a Tree and returns a list of the elements in its node in a preorder traversal but I ca n't get it to work .
ner_tags: O O O O O O O O O O O O O O B-Language O O O O O O B-Language O O O O B-Data_Structure O O O B-Data_Structure O O O O O O O O O O O O O O O O O O O