class_docstr: This class is used to extract nouns, proper nouns, phrases from text, including descriptions and
  url links
class_docstr_tok: ["This","class","is","used","to","extract","nouns",",","proper","nouns",",","phrases","from","text",",","including","descriptions","and","url","links"]
code: def category2words(self, categories):
      words = []
      for cat in categories:
          cat_str = " ".join(cat.split("_"))
          words.extend(self.extract_nouns(cat_str))
      return list(set(words))
  
imports: from sematch.utility import FileIO
  from nltk.stem import WordNetLemmatizer
  from nltk.corpus import wordnet
  import nltk
  from collections import Counter
  import itertools
  import string
  import re
label_desc: Use image node_id 8 for calling the Extraction obj's underlying member method code with example usage: obj.category2words(categories) and returns: list