code: def run_test(filename, funcs, args=[0]):
      nargs = len(args)
      if len(funcs) > 1 and nargs > 1:
          raise ValueError("nargs > 1 and len(funcs) > 1 not supported")
  
      data = parse_txt_data(filename)
      if data.shape[1] != len(funcs) + nargs:
          raise ValueError(
              "data has %d items / row, but len(funcs) = %d and "
              "nargs = %d" % (data.shape[1], len(funcs), nargs)
          )
  
      if nargs > 1:
          f = funcs[0]
          x = [data[args[i]] for i in nargs]
          return f(*x)
      else:
          y = [
              f(data[:, 0]) - data[:, idx + 1]
              for idx, f in enumerate(funcs)
          ]
  
          return data[:, 0], y
  
label_desc: Use image node_id 2 for calling a global function with example usage: run_test(filename, funcs, args) and returns: f, data,  y