code: def forward(self, x):
      x = self.conv(x)
      x = self.bn(x)
      if self.use_act:
          x = self.act(x)
      return x
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle.nn.initializer import KaimingNormal, Constant
  from paddle.nn import Conv2D, BatchNorm2D, ReLU, AdaptiveAvgPool2D, MaxPool2D
  from paddle.regularizer import L2Decay
  from paddle import ParamAttr
label_desc: Use image node_id 2 for calling the ConvBNAct obj's underlying member method code with example usage: obj.forward(x) and returns: x