code: def affine_transform(pt, t):
      new_pt = np.array([pt[0], pt[1], 1.0]).T
      new_pt = np.dot(t, new_pt)
      return new_pt[:2]
  
imports: import os
  import copy
  import math
  import time
  import yaml
  import cv2
  import numpy
  from collections import defaultdict
  import paddle
  from benchmark_utils import PaddleInferBenchmark
  from utils import gaussian_radius, gaussian2D, draw_umich_gaussian
  from preprocess import preprocess, decode_image, WarpAffine, NormalizeImage, Permute
  from utils import argsparser, Timer, get_current_memory_mb
  from infer import Detector, get_test_images, print_arguments, bench_log, PredictConfig
  from keypoint_preprocess import get_affine_transform
  import sys
  from pptracking.python.mot import CenterTracker
  from pptracking.python.mot.utils import MOTTimer, write_mot_results
  from pptracking.python.mot.visualize import plot_tracking
label_desc: Use image node_id 2 for calling a global function with example usage: affine_transform(pt, t) and returns: new_pt