code: def similarity(w1, w2, threshold=0.5):
      
      ratio = SM(None, str(w1).lower(), str(w2).lower()).ratio()
      return ratio if ratio > threshold else 0
docs: compare two strings 'words', and
      return ratio of smiliarity, be it larger than the threshold,
      or 0 otherwise.
  
      NOTE: if the result more like junk, increase the threshold value.