new_contents: # copied on Mon., Aug. 15th, 2016 from https://en.wikibooks.org/wiki/Algorithm_Implementation/Strings/Levenshtein_distance#Python
  
  # Christopher P. Matthews
  # christophermatthews1985@gmail.com
  # Sacramento, CA, USA
  
  def levenshtein(s, t):
      ''' From Wikipedia article; Iterative with two matrix rows. '''
      if s == t: return 0
      elif len(s) == 0: return len(t)
      elif len(t) == 0: return len(s)
      v0 = [None] * (len(t) + 1)
      v1 = [None] * (len(t) + 1)
      for i in range(len(v0)):
          v0[i] = i
      for i in range(len(s)):
          v1[0] = i + 1
          for j in range(len(t)):
              cost = 0 if s[i] == t[j] else 1
              v1[j + 1] = min(v1[j] + 1, v0[j + 1] + 1, v0[j] + cost)
          for j in range(len(v0)):
              v0[j] = v1[j]
      return v1[len(t)]
subject: use .py