code: def forward(self, x):
      f = x[:3]
      h0 = self.h0_conv(f[0])
      h1 = self.h1_conv(f[1])
      h2 = self.h2_conv(f[2])
      g0 = self.g0_conv(h0)
      g1 = paddle.add(x=g0, y=h1)
      g1 = F.relu(g1)
      g1 = self.g1_conv(g1)
      g2 = paddle.add(x=g1, y=h2)
      g2 = F.relu(g2)
      g2 = self.g2_conv(g2)
      return g2
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import paddle
  from paddle import nn
  import paddle.nn.functional
  from paddle import ParamAttr
label_desc: Use image node_id 2 for calling the FPN_Down_Fusion obj's underlying member method code with example usage: obj.forward(x) and returns: g2