code: def forward(self, x):
      x = self._conv(x)
      x = self._batch_norm(x)
      return x
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg.cvlibs import manager, param_init
  from paddleseg.models import layers
  from paddleseg.utils import utils
label_desc: Use image node_id 2 for calling the _ConvBN obj's underlying member method code with example usage: obj.forward(x) and returns: x