code: def _generate_anchor_point(self, feat_sizes, strides, offset=0.0):
      anchor_points, stride_tensor = [], []
      num_anchors_list = []
      for feat_size, stride in zip(feat_sizes, strides):
          h, w = feat_size
          x = (paddle.arange(w) + offset) * stride
          y = (paddle.arange(h) + offset) * stride
          y, x = paddle.meshgrid(y, x)
          anchor_points.append(
              paddle.stack([x, y], axis=-1).reshape([-1, 2])
          )
          stride_tensor.append(
              paddle.full(
                  [len(anchor_points[-1]), 1], stride, dtype=self._dtype
              )
          )
          num_anchors_list.append(len(anchor_points[-1]))
      anchor_points = paddle.concat(anchor_points).astype(self._dtype)
      anchor_points.stop_gradient = True
      stride_tensor = paddle.concat(stride_tensor)
      stride_tensor.stop_gradient = True
      return anchor_points, stride_tensor, num_anchors_list
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle import ParamAttr
  from paddle.regularizer import L2Decay
  from ppdet.core.workspace import register
  import math
  import numpy
  from ..initializer import bias_init_with_prob, constant_
  from ..backbones.csp_darknet import BaseConv, DWConv
  from ..losses import IouLoss
  from ppdet.modeling.assigners.simota_assigner import SimOTAAssigner
  from ppdet.modeling.bbox_utils import bbox_overlaps
  from ppdet.modeling.layers import MultiClassNMS
label_desc: Use image node_id 4 for calling the YOLOXHead obj's underlying member method code with example usage: obj._generate_anchor_point(feat_sizes, strides, offset) and returns: anchor_points,  stride_tensor,  num_anchors_list