code: def forward(self, input_features, gating_features):
      cat = paddle.concat([input_features, gating_features], axis=1)
      alphas = self._gate_conv(cat)
      x = input_features * (alphas + 1)
      x = self.conv(x)
      return x
  
imports: from collections import defaultdict
  import time
  import paddle
  import paddle.nn
  import paddle.nn.functional
  import paddleseg
  from paddleseg.models import layers
  from paddleseg import utils
  from paddleseg.cvlibs import manager
  from ppmatting.models.losses import MRSD, GradientLoss
  from ppmatting.models.backbone import resnet_vd
label_desc: Use image node_id 2 for calling the GatedSpatailConv2d obj's underlying member method code with example usage: obj.forward(input_features, gating_features) and returns: x