class_docstr: Learning to downsample module.
  This module consists of three downsampling blocks (one conv and two separable conv)
  Args:
      dw_channels1 (int, optional): The input channels of the first sep conv. Default: 32.
      dw_channels2 (int, optional): The input channels of the second sep conv. Default: 48.
      out_channels (int, optional): The output channels of LearningToDownsample module. Default: 64.
code: def forward(self, x):
      x = self.conv_bn_relu(x)
      x = self.dsconv_bn_relu1(x)
      x = self.dsconv_bn_relu2(x)
      return x
  
imports: import paddle.nn
  import paddle.nn.functional
  import paddle
  from paddleseg.cvlibs import manager
  from paddleseg.models import layers
  from paddleseg.utils import utils
label_desc: Use image node_id 2 for calling the LearningToDownsample obj's underlying member method code with example usage: obj.forward(x) and returns: x