code: def test_strip_functional_tags(self):
      ptb_reader = PennTreeBankConstituencySpanDatasetReader()
      # Get gold spans should strip off all the functional tags.
      tree = Tree.fromstring(
          "(S (NP=PRP (D the) (N dog)) (VP-0 (V chased) (NP|FUN-TAGS (D the) (N cat))))"
      )
      ptb_reader._strip_functional_tags(tree)
      assert tree == Tree.fromstring(
          "(S (NP (D the) (N dog)) (VP (V chased) (NP (D the) (N cat))))"
      )
  
file_path: magnitude/pymagnitude/third_party/allennlp/tests/data/dataset_readers/penn_tree_bank_reader_test.py
imports: from __future__ import division
  from __future__ import absolute_import
  from nltk.tree import Tree
  from allennlp.data.dataset_readers import PennTreeBankConstituencySpanDatasetReader
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.data.dataset_readers.dataset_utils.span_utils import enumerate_spans
label_desc: Use image node_id 3 for calling the TestPennTreeBankConstituencySpanReader obj's underlying member method code with example usage: obj.test_strip_functional_tags() without return types