code: def test_get_terms_to_display(self):
      df = DiachronicTermMiner(
          self.corpus, num_terms=10
      ).get_display_dataframe()
      self.assertEquals(
          list(df.columns),
          ["term", "variable", "frequency", "trending"],
      )
      self.assertEquals(len(set(df.term)), 10)
      df = DiachronicTermMiner(
          self.corpus, num_terms=20
      ).get_display_dataframe()
      self.assertEquals(len(set(df.term)), 20)
  
file_path: scattertext/scattertext/test/test_diachronicTermMiner.py
imports: from unittest import TestCase
  import io
  import pandas
  from scattertext.CorpusFromParsedDocuments import CorpusFromParsedDocuments
  from scattertext.WhitespaceNLP import whitespace_nlp_with_sentences
  from scattertext.diachronic.DiachronicTermMiner import DiachronicTermMiner
label_desc: Use image node_id 3 for calling the TestDiachronicTermMiner obj's underlying member method code with example usage: obj.test_get_terms_to_display() without return types