code: def test_removefilter(self):
      filter_three = MyFilter()
      self.percolator.removefilter(self.filter_two)
      self.assertEqual(self.percolator.top, self.filter_one)
      self.assertIsNone(self.filter_two.delegate)
  
      filter_three = MyFilter()
      self.percolator.insertfilter(self.filter_two)
      self.percolator.insertfilter(filter_three)
      self.percolator.removefilter(self.filter_one)
      self.assertEqual(self.percolator.top, filter_three)
      self.assertEqual(filter_three.delegate, self.filter_two)
      self.assertEqual(self.filter_two.delegate, self.percolator.bottom)
      self.assertIsNone(self.filter_one.delegate)
  
imports: from idlelib.percolator import Percolator, Delegator
  import unittest
  from test.support import requires
  from tkinter import Text, Tk, END
label_desc: Use image node_id 6 for calling the PercolatorTest obj's underlying member method code with example usage: obj.test_removefilter() without return types