class_docstr: The head of PPLiteSeg.
  
  Args:
      backbone_out_chs (List(Tensor)): The channels of output tensors in the backbone.
      arm_out_chs (List(int)): The out channels of each arm module.
      cm_bin_sizes (List(int)): The bin size of context module.
      cm_out_ch (int): The output channel of the last context module.
      arm_type (str): The type of attention refinement module.
      resize_mode (str): The resize mode for the upsampling operation in decoder.
docstr: Args:
      in_feat_list (List(Tensor)): Such as [x2, x4, x8, x16, x32].
          x2, x4 and x8 are optional.
  Returns:
      out_feat_list (List(Tensor)): Such as [x2, x4, x8, x16, x32].
          x2, x4 and x8 are optional.
          The length of in_feat_list and out_feat_list are the same.
docstr_tok: ["Args",":","in_feat_list","(","List","(","Tensor",")",")",":","Such","as","[","x2",",","x4",",","x8",",","x16",",","x32","]",".","x2",",","x4","and","x8","are","optional",".","Returns",":","out_feat_list","(","List","(","Tensor",")",")",":","Such","as","[","x2",",","x4",",","x8",",","x16",",","x32","]",".","x2",",","x4","and","x8","are","optional",".","The","length","of","in_feat_list","and","out_feat_list","are","the","same","."]
code: def forward(self, in_feat_list):
      """
      Args:
          in_feat_list (List(Tensor)): Such as [x2, x4, x8, x16, x32].
              x2, x4 and x8 are optional.
      Returns:
          out_feat_list (List(Tensor)): Such as [x2, x4, x8, x16, x32].
              x2, x4 and x8 are optional.
              The length of in_feat_list and out_feat_list are the same.
      """
  
      high_feat = self.cm(in_feat_list[-1])
      out_feat_list = []
  
      for i in reversed(range(len(in_feat_list))):
          low_feat = in_feat_list[i]
          arm = self.arm_list[i]
          high_feat = arm(low_feat, high_feat)
          out_feat_list.insert(0, high_feat)
  
      return out_feat_list
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg import utils
  from paddleseg.models import layers
  from paddleseg.cvlibs import manager
  from paddleseg.utils import utils
label_desc: Use image node_id 2 for calling the PPLiteSegHead obj's underlying member method code with example usage: obj.forward(in_feat_list) and returns: out_feat_list