code: def _get_model(self):
      return (
          self.model_
          if self.model_ is not None
          else LogisticRegression(penalty="l2")
      )
  
file_path: scattertext/scattertext/diachronic/DiachronicTermMiner.py
imports: import numpy
  import pandas
  from sklearn.linear_model import LogisticRegression
  from scattertext.diachronic.BubbleDiachronicVisualization import BubbleDiachronicVisualization
  from scattertext.diachronic.DiachronicVisualizer import DiachronicVisualizer
label_desc: Use image node_id 5 for calling the DiachronicTermMiner obj's underlying member method code with example usage: obj._get_model() and returns: unknown