code: def test_percentile_cutoff_top_p(self):
      expected = self.df.loc[:, ["B", "C"]]
      result = msno.nullity_filter(self.df, p=0.6, filter="top")
      assert result.equals(expected)
  
imports: import unittest
  import pandas
  import numpy
  import sys
  import missingno
label_desc: Use image node_id 3 for calling the TestNullityFilter obj's underlying member method code with example usage: obj.test_percentile_cutoff_top_p() without return types