code: def GetNumExtraNgrams(self):
      ans = 0
      for hist_len in range(
          args.no_backoff_ngram_order, args.ngram_order
      ):
          # note: hist_len + 1 is the actual order.
          ans += self.GetNumNgrams(hist_len)
      return ans
  
imports: import argparse
  import math
  import sys
  from collections import defaultdict
label_desc: Use image node_id 18 for calling the NgramCounts obj's underlying member method code with example usage: obj.GetNumExtraNgrams() and returns: ans