docstr: Add root if necessary to specified fileid.
docstr_tok: ["Add","root","if","necessary","to","specified","fileid","."]
code: def add_root(self, fileid):
      """
      Add root if necessary to specified fileid.
      """
      if self.root in fileid:
          return fileid
      return self.root + fileid
  
imports: import functools
  import os
  import re
  import tempfile
  from nltk.corpus.reader.util import concat
  from nltk.corpus.reader.xmldocs import XMLCorpusReader, XMLCorpusView
label_desc: Use image node_id 5 for calling the NKJPCorpusReader obj's underlying member method code with example usage: obj.add_root(fileid) and returns: unknown, fileid