code: def find_class(s, index):
      lines = s[:index].split("\n")
      while lines:
          m = CLASS_DEF_RE.match(lines[-1])
          if m:
              return m.group(1) + "."
          lines.pop()
      return "?."
  
file_path: nltk/tools/find_deprecated.py
imports: import os
  import re
  import sys
  import textwrap
  import tokenize
  from doctest import DocTestParser, register_optionflag
  from cStringIO import StringIO
  import nltk.corpus
  from nltk import defaultdict
label_desc: Use image node_id 2 for calling a global function with example usage: find_class(s, index) and returns: str, unknown