code: def test_get_scaled_f_scores_vs_background(self):
      df = self.term_cat_freq.get_scaled_f_scores_vs_background()
      self.assertGreater(len(df), 20)
      self.assertEqual(sum(df.corpus > 0), 3)
      self.assertEqual(
          set(df.columns), {"corpus", "background", "Scaled f-score"}
      )
  
file_path: scattertext/scattertext/test/test_termCategoryFrequencies.py
imports: from unittest import TestCase
  import numpy
  import pandas
  from scattertext.ScatterChartData import ScatterChartData
  from scattertext.TermCategoryFrequencies import TermCategoryFrequencies
label_desc: Use image node_id 4 for calling the TestTermCategoryFrequencies obj's underlying member method code with example usage: obj.test_get_scaled_f_scores_vs_background() without return types