code: def set_num_threads(cls, n):
      if n < 1:
          n = cpu_count()
      cls.num_threads = n
      set_num_threads(n)
      ch.set_num_threads(n)
  
file_path: ffcv/ffcv/pipeline/compiler.py
imports: import pdb
  from numba import njit, set_num_threads, prange, warnings, get_num_threads
  from numba.core.errors import NumbaPerformanceWarning
  from multiprocessing import cpu_count
  import torch
  import warnings
label_desc: Use image node_id 2 for calling the Compiler obj's underlying member method code with example usage: obj.set_num_threads(cls, n) without return types