code: def forward(self, x):
      B, N, C = x.shape
      x = paddle.reshape(x, [B, self.resolution, self.resolution, C])
      end1, end2 = x.shape[1], x.shape[2]
      x = x[:, 0 : end1 : self.stride, 0 : end2 : self.stride]
      x = paddle.reshape(x, [B, -1, C])
      return x
  
imports: import itertools
  import math
  import warnings
  import paddle
  import paddle.nn
  import paddle.nn.functional
  from paddle.nn.initializer import Constant
  from paddle.nn.initializer import TruncatedNormal
  from paddle.regularizer import L2Decay
  from .vision_transformer import Identity
  from .vision_transformer import ones_
  from .vision_transformer import trunc_normal_
  from .vision_transformer import zeros_
label_desc: Use image node_id 2 for calling the Subsample obj's underlying member method code with example usage: obj.forward(x) and returns: x