code: def time_diff(self, size, soltype):
      if soltype == "fft":
          diff(self.f, 3)
      else:
          direct_diff(self.f, 3)
  
file_path: scipy/benchmarks/benchmarks/fftpack_pseudo_diffs.py
imports: from numpy import arange, sin, cos, pi, exp, tanh, sign
  from .common import Benchmark, safe_import
label_desc: Use image node_id 2 for calling the Bench obj's underlying member method code with example usage: obj.time_diff(size, soltype) without return types