code: def __str__(self):
      return str(self._id)
  
imports: from __future__ import absolute_import
  import cv2
  import numpy
  import math
  import copy
  import random
  import uuid
  from numbers import Number, Integral
  from ...modeling.keypoint_utils import get_affine_mat_kernel, warp_affine_joints, get_affine_transform, affine_transform, get_warp_matrix
  from ppdet.core.workspace import serializable
  from ppdet.utils.logger import setup_logger
  import matplotlib.pyplot
  from PIL import Image, ImageDraw
  from mpl_toolkits.mplot3d import Axes3D
label_desc: Use image node_id 4 for calling the BaseOperator obj's underlying member method code with example usage: obj.__str__() and returns: str