code: def _get_mean_delta(self, cat_X, ncat_X):
      return np.array(cat_X.mean(axis=0) - ncat_X.mean(axis=0))[0]
  
imports: from abc import ABCMeta, abstractmethod
  from typing import Tuple
  import numpy
  import pandas
  from scattertext.ParsedCorpus import ParsedCorpus
  from scipy import stats
  from scipy.sparse import vstack
  from scattertext.util import inherits_from
  from scattertext.termranking import AbsoluteFrequencyRanker
  from scattertext.termranking.TermRanker import TermRanker
label_desc: Use image node_id 16 for calling the CorpusBasedTermScorer obj's underlying member method code with example usage: obj._get_mean_delta(cat_X, ncat_X) and returns: np