code: def forward_eval(self, feats):
      if self.eval_size:
          anchor_points, stride_tensor = (
              self.anchor_points,
              self.stride_tensor,
          )
      else:
          anchor_points, stride_tensor = self._generate_anchors(feats)
      cls_score_list, reg_dist_list = [], []
      for i, feat in enumerate(feats):
          _, _, h, w = feat.shape
          l = h * w
          avg_feat = F.adaptive_avg_pool2d(feat, (1, 1))
          cls_logit = self.pred_cls[i](
              self.stem_cls[i](feat, avg_feat) + feat
          )
          reg_dist = self.pred_reg[i](self.stem_reg[i](feat, avg_feat))
          reg_dist = reg_dist.reshape(
              [-1, 4, self.reg_channels, l]
          ).transpose([0, 2, 3, 1])
          if self.use_shared_conv:
              reg_dist = self.proj_conv(
                  F.softmax(reg_dist, axis=1)
              ).squeeze(1)
          else:
              reg_dist = F.softmax(reg_dist, axis=1)
          # cls and reg
          cls_score = F.sigmoid(cls_logit)
          cls_score_list.append(
              cls_score.reshape([-1, self.num_classes, l])
          )
          reg_dist_list.append(reg_dist)
  
      cls_score_list = paddle.concat(cls_score_list, axis=-1)
      if self.use_shared_conv:
          reg_dist_list = paddle.concat(reg_dist_list, axis=1)
      else:
          reg_dist_list = paddle.concat(reg_dist_list, axis=2)
          reg_dist_list = self.proj_conv(reg_dist_list).squeeze(1)
  
      return cls_score_list, reg_dist_list, anchor_points, stride_tensor
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from ppdet.core.workspace import register
  from paddle import ParamAttr
  from paddle.nn.initializer import KaimingNormal
  from paddle.nn.initializer import Normal, Constant
  from ..bbox_utils import batch_distance2bbox
  from ..losses import GIoULoss
  from ..initializer import bias_init_with_prob, constant_, normal_
  from ..assigners.utils import generate_anchors_for_grid_cell
  from ppdet.modeling.backbones.cspresnet import ConvBNLayer, RepVggBlock
  from ppdet.modeling.ops import get_static_shape, get_act_fn
  from ppdet.modeling.layers import MultiClassNMS
label_desc: Use image node_id 6 for calling the PPYOLOEHead obj's underlying member method code with example usage: obj.forward_eval(feats) and returns: cls_score_list,  reg_dist_list,  anchor_points,  stride_tensor