code: def _split(self, string):
          
          for i in range(len(string) - self.N + 1):
              yield string[i:i + self.N]
docs: Iterates over the ngrams of a string (no padding).
  
          >>> from ngram import NGram
          >>> n = NGram()
          >>> list(n._split("hamegg"))
          ['ham', 'ame', 'meg', 'egg']