code: def test_is_enabled(self):
      self.assertIs(interfaces.cache._fftw_cache, None)
  
      interfaces.cache.enable()
      self.assertTrue(interfaces.cache.is_enabled())
  
      interfaces.cache.disable()
      self.assertFalse(interfaces.cache.is_enabled())
  
imports: import copy
  import sys
  from pyfftw import interfaces, builders
  import pyfftw
  import numpy
  import numpy
  import unittest
  from .test_pyfftw_base import run_test_suites, miss
  from .test_pyfftw_numpy_interface import InterfacesNumpyFFTTestFFT
  import threading
  import time
  import os
  import hashlib
label_desc: Use image node_id 2 for calling the InterfacesCacheTest obj's underlying member method code with example usage: obj.test_is_enabled() without return types