code: def test_namespaces(self):
      self.assertTrue(self.top.lookup("Mine").is_namespace())
      self.assertTrue(self.Mine.lookup("a_method").is_namespace())
      self.assertTrue(self.top.lookup("spam").is_namespace())
      self.assertTrue(self.spam.lookup("internal").is_namespace())
      self.assertTrue(self.top.lookup("namespace_test").is_namespace())
      self.assertFalse(self.spam.lookup("x").is_namespace())
  
      self.assertTrue(
          self.top.lookup("spam").get_namespace() is self.spam
      )
      ns_test = self.top.lookup("namespace_test")
      self.assertEqual(len(ns_test.get_namespaces()), 2)
      self.assertRaises(ValueError, ns_test.get_namespace)
  
      ns_test_2 = self.top.lookup("glob")
      self.assertEqual(len(ns_test_2.get_namespaces()), 0)
      self.assertRaises(ValueError, ns_test_2.get_namespace)
  
imports: import symtable
  import unittest
  from test import support
  from test.support import os_helper
label_desc: Use image node_id 15 for calling the SymtableTest obj's underlying member method code with example usage: obj.test_namespaces() without return types