class_docstr: Grammar subclass that reads classic pgen output files.
  
  The run() method reads the tables as produced by the pgen parser
  generator, typically contained in two C files, graminit.h and
  graminit.c.  The other methods are for internal use only.
  
  See the base class for more documentation.
docstr: Create additional useful structures.  (Internal).
docstr_tok: ["Create","additional","useful","structures",".","(","Internal",")","."]
code: def finish_off(self):
      """Create additional useful structures.  (Internal)."""
      self.keywords = {}  # map from keyword strings to arc labels
      self.tokens = {}  # map from numeric token values to arc labels
      for ilabel, (type, value) in enumerate(self.labels):
          if type == token.NAME and value is not None:
              self.keywords[value] = ilabel
          elif value is None:
              self.tokens[type] = ilabel
  
file_path: black/src/blib2to3/pgen2/conv.py
imports: import re
  from pgen2 import grammar, token
label_desc: Use image node_id 4 for calling the Converter obj's underlying member method code with example usage: obj.finish_off() without return types