code: def save_wisdom(wisdomfile):
      
      if wisdomfile is None:
          return
  
      if wisdomfile:
          pickle.dump(
              pyfftw.export_wisdom(), open(wisdomfile, 'wb'),
              protocol=2
          )
docs: Save the acquired 'wisdom' generated by FFTW to file so that future
      initializations of FFTW will be faster.