code: def edit_distance_2(self, word):
          
          word = word.lower()
          return [
              e2 for e1 in self.edit_distance_1(word) for e2 in self.edit_distance_1(e1)
          ]
docs: Compute all strings that are two edits away from `word` using only
              the letters in the corpus
  
              Args:
                  word (str): The word for which to calculate the edit distance
              Returns:
                  set: The set of strings that are edit distance two from the \
                  provided word