code: def generate_anchor(self, nGh, nGw, anchor_hw):
      nA = len(anchor_hw)
      yy, xx = np.meshgrid(np.arange(nGh), np.arange(nGw))
  
      mesh = np.stack([xx.T, yy.T], axis=0)  # [2, nGh, nGw]
      mesh = np.repeat(mesh[None, :], nA, axis=0)  # [nA, 2, nGh, nGw]
  
      anchor_offset_mesh = anchor_hw[:, :, None][:, :, :, None]
      anchor_offset_mesh = np.repeat(anchor_offset_mesh, nGh, axis=-2)
      anchor_offset_mesh = np.repeat(anchor_offset_mesh, nGw, axis=-1)
  
      anchor_mesh = np.concatenate(
          [mesh, anchor_offset_mesh], axis=1
      )  # [nA, 4, nGh, nGw]
      return anchor_mesh
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from numbers import Integral
  import cv2
  import copy
  import numpy
  import random
  import math
  from .operators import BaseOperator, register_op
  from .batch_operators import Gt2TTFTarget
  from ppdet.modeling.bbox_utils import bbox_iou_np_expand
  from ppdet.utils.logger import setup_logger
  from .op_helper import gaussian_radius
label_desc: Use image node_id 2 for calling the Gt2JDETargetThres obj's underlying member method code with example usage: obj.generate_anchor(nGh, nGw, anchor_hw) and returns: anchor_mesh