code: def forward(self, x):
      # x: b, c, w, h
      x = self.conv1(x)
      x = x.transpose([0, 2, 3, 1])  # b, w, h, c
      batch_size, w, h, c = x.shape
      x = x.reshape([-1, h, c])  # b*w, h, c
      x, _ = self.gru(x)
      x = x.reshape([-1, w, h, c])
      x = x.transpose([0, 3, 1, 2])
      return x
  
imports: import math
  import paddle
  import paddle.nn.functional
  from paddle import nn
  from collections import OrderedDict
  import sys
  import numpy
  import warnings
  import math, copy
  import cv2
  from .tps_spatial_transformer import TPSSpatialTransformer
  from .stn import STN
  from ppocr.modeling.heads.sr_rensnet_transformer import Transformer
label_desc: Use image node_id 2 for calling the GruBlock obj's underlying member method code with example usage: obj.forward(x) and returns: x