code: def forward(self, x):
      x = self.conv(x)
      x = self.bn(x)
      if self.act:
          x = self.relu(x)
      return x
  
imports: import math
  import paddle
  from paddle import ParamAttr
  import paddle.nn
  from paddle.nn import Conv2D, BatchNorm, Linear
  from paddle.nn import AdaptiveAvgPool2D, MaxPool2D, AvgPool2D
  from paddle.nn.initializer import Uniform, Constant, KaimingNormal
label_desc: Use image node_id 2 for calling the ConvBNLayer obj's underlying member method code with example usage: obj.forward(x) and returns: x