class_docstr: Make the size of feature map divisible by local group size.
class_docstr_tok: ["Make","the","size","of","feature","map","divisible","by","local","group","size","."]
code: def depad_if_needed(self, x, size):
      n, h, w, c = size
      pad_h = paddle.cast(
          paddle.ceil(h / self.lgs[0]) * self.lgs[0] - h, paddle.int32
      ).reshape([-1])
      pad_w = paddle.cast(
          paddle.ceil(w / self.lgs[1]) * self.lgs[1] - w, paddle.int32
      ).reshape([-1])
      if pad_h > 0 or pad_w > 0:  # remove the center-padding on feature
          return x[
              :,
              pad_h // 2 : pad_h // 2 + h,
              pad_w // 2 : pad_w // 2 + w,
              :,
          ]
      return x
  
imports: import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddleseg.cvlibs import manager, param_init
  from paddleseg.models import layers
  from paddleseg.utils import utils, logger
  from paddleseg.models.backbones.transformer_utils import *
label_desc: Use image node_id 3 for calling the PadHelper obj's underlying member method code with example usage: obj.depad_if_needed(x, size) and returns: x, x