class_docstr: DmlCorpus implements a collection of articles. It is initialized via a DmlConfig
  object, which holds information about where to look for the articles and how
  to process them.
  
  Apart from being a regular corpus (bag-of-words iterable with a `len()` method),
  DmlCorpus has methods for building a dictionary (mapping between words and
  their ids).
code: def saveDictionary(self, fname):
      logger.info("saving dictionary mapping to %s", fname)
      fout = open(fname, "w")
      for tokenId, token in self.dictionary.id2token.iteritems():
          fout.write("%i\t%s\n" % (tokenId, token))
      fout.close()
  
imports: import logging
  import os.path
  from gensim import interfaces, matutils
  import dictionary
label_desc: Use image node_id 6 for calling the DmlCorpus obj's underlying member method code with example usage: obj.saveDictionary(fname) without return types