code: def forward(self, x):
      if self.act is not None:
          x = self.act(x)
      out = self.depthwise_conv(x)
      out = self.pointwise_conv(out)
      if self.norm_type is not None:
          out = self.norm(out)
      return out
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle import ParamAttr
  from paddle.nn.initializer import Constant
  from ppdet.core.workspace import register, serializable
  from ppdet.modeling.layers import ConvNormLayer
  from ..shape_spec import ShapeSpec
label_desc: Use image node_id 2 for calling the SeparableConvLayer obj's underlying member method code with example usage: obj.forward(x) and returns: out