class_docstr: Pyramid Pooling Module that only concat the features of each layer.
  
  Args:
      pool_scales (tuple[int]): Pooling scales used in Pooling Pyramid
          Module.
docstr: Forward function.
docstr_tok: ["Forward","function","."]
code: def forward(self, feats):
      """Forward function."""
      ppm_outs = []
      for ppm in self:
          ppm_out = ppm(feats)
          ppm_outs.append(ppm_out.view(*feats.shape[:2], -1))
      concat_outs = torch.cat(ppm_outs, dim=2)
      return concat_outs
  
imports: import torch
  import torch.nn
  from annotator.uniformer.mmcv.cnn import ConvModule
  from ..builder import HEADS
  from ..utils import SelfAttentionBlock
  from .decode_head import BaseDecodeHead
label_desc: Use image node_id 2 for calling the PPMConcat obj's underlying member method code with example usage: obj.forward(feats) and returns: concat_outs