code: def _vgg(self):
      self.conv1, self.pool1 = conv_block(
          self.image, 2, [64] * 2, [3] * 2
      )
      self.conv2, self.pool2 = conv_block(
          self.pool1, 2, [128] * 2, [3] * 2
      )
  
      # priorbox min_size is 16
      self.conv3, self.pool3 = conv_block(
          self.pool2, 3, [256] * 3, [3] * 3
      )
      # priorbox min_size is 32
      self.conv4, self.pool4 = conv_block(
          self.pool3, 3, [512] * 3, [3] * 3
      )
      # priorbox min_size is 64
      self.conv5, self.pool5 = conv_block(
          self.pool4, 3, [512] * 3, [3] * 3
      )
  
      # fc6 and fc7 in paper, priorbox min_size is 128
      self.conv6 = conv_block(
          self.pool5, 2, [1024, 1024], [3, 1], with_pool=False
      )
      # conv6_1 and conv6_2 in paper, priorbox min_size is 256
      self.conv7 = conv_block(
          self.conv6, 2, [256, 512], [1, 3], [1, 2], with_pool=False
      )
      # conv7_1 and conv7_2 in paper, priorbox mini_size is 512
      self.conv8 = conv_block(
          self.conv7, 2, [128, 256], [1, 3], [1, 2], with_pool=False
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  import six
  import paddle.fluid
  from paddle.fluid.param_attr import ParamAttr
  from paddle.fluid.initializer import Xavier
  from paddle.fluid.initializer import Constant
  from paddle.fluid.initializer import Bilinear
  from paddle.fluid.regularizer import L2Decay
label_desc: Use image node_id 4 for calling the PyramidBox obj's underlying member method code with example usage: obj._vgg() without return types