code: def forward(self, inputs):
      x = inputs["image"]
      x = self.stem(x)
      outs = []
      for idx, stage in enumerate(self.stages):
          if self.use_checkpoint and self.training:
              x = paddle.distributed.fleet.utils.recompute(
                  stage, x, **{"preserve_rng_state": True}
              )
          else:
              x = stage(x)
          if idx in self.return_idx:
              outs.append(x)
  
      return outs
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle import ParamAttr
  from paddle.regularizer import L2Decay
  from paddle.nn.initializer import Constant
  from ppdet.modeling.ops import get_act_fn
  from ppdet.core.workspace import register, serializable
  from ..shape_spec import ShapeSpec
label_desc: Use image node_id 2 for calling the CSPResNet obj's underlying member method code with example usage: obj.forward(inputs) and returns: outs