code: def get_cards():
      """
      get gpu cards number
      """
      num = 0
      cards = os.environ.get("CUDA_VISIBLE_DEVICES", "")
      if cards != "":
          num = len(cards.split(","))
      return num
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  from __future__ import absolute_import
  import os
label_desc: Use image node_id 1 for calling a global function with example usage: get_cards() and returns: num