class_docstr: class that supplies part of speech tags using NLTK
  note: avoids the NLTK downloader (see __init__ method)
code: def tag_tokens(self, tokens):
      word_pos_pairs = self.tagger.tag(tokens)
      return {
          "tokens": tokens,
          "pos": [tag for (w, tag) in word_pos_pairs],
      }
  
imports: from __future__ import print_function
  import os
  import re
  import sys
  from collections import Counter
label_desc: Use image node_id 3 for calling the NLTKTagger obj's underlying member method code with example usage: obj.tag_tokens(tokens) and returns: dict