code: def test_active_trail_nodes(self):
      self.assertListEqual(
          sorted(self.G2.active_trail_nodes("d")), ["d", "g", "l", "s"]
      )
      self.assertListEqual(
          sorted(self.G2.active_trail_nodes("g")), ["d", "g", "l", "s"]
      )
      self.assertListEqual(
          sorted(self.G2.active_trail_nodes("l")), ["d", "g", "l", "s"]
      )
      self.assertListEqual(
          sorted(self.G2.active_trail_nodes("s")), ["d", "g", "l", "s"]
      )
  
imports: import unittest
  import networkx
  import pandas
  import numpy
  from pgmpy.models import NaiveBayes
  from pgmpy.independencies import Independencies
label_desc: Use image node_id 3 for calling the TestNaiveBayesMethods obj's underlying member method code with example usage: obj.test_active_trail_nodes() without return types