code: def _ninf_array(shape):
      res = np.empty(shape, np.float64)
      res.fill(-np.inf)
      return res
  
imports: import itertools
  import re
  from nltk.metrics import accuracy
  from nltk.probability import ConditionalFreqDist, ConditionalProbDist, DictionaryConditionalProbDist, DictionaryProbDist, FreqDist, LidstoneProbDist, MLEProbDist, MutableProbDist, RandomProbDist
  from nltk.tag.api import TaggerI
  from nltk.util import LazyMap, unique_list
label_desc: Use image node_id 2 for calling a global function with example usage: _ninf_array(shape) and returns: res