code: def time_dft(self, size):
      sl.dft(size)
  
imports: import math
  import numpy.linalg
  import numpy
  from numpy.testing import assert_
  from numpy.random import rand
  from .common import Benchmark, safe_import
label_desc: Use image node_id 6 for calling the SpecialMatrices obj's underlying member method code with example usage: obj.time_dft(size) without return types