code: def tree2str(tree, concat=" "):
      """Convert a nltk.tree.Tree to a string.
  
      For example:
          (NP a/DT beautiful/JJ new/JJ dashboard/NN) -> "a beautiful dashboard"
      """
      return concat.join([word for (word, tag) in tree])
  
imports: import re
  import string
label_desc: Use image node_id 3 for calling a global function with example usage: tree2str(tree, concat) and returns: concat