code: def forward(self, x):
      x = self.linear1(x)
      x = self.linear2(x)
      x = self.linear3(x)
      x = self.linear4(x)
      return x
  
file_path: colossalai/tests/test_fx/test_parallel_1d.py
imports: import pytest
  import torch
  from torch.fx import symbolic_trace
  from colossalai.fx.passes import column_shard_linear_pass
  from colossalai.initialize import launch
  from colossalai.legacy.core import global_context
  from colossalai.logging import disable_existing_loggers
  from colossalai.testing import clear_cache_before_run, rerun_if_address_is_in_use, spawn
label_desc: Use image node_id 2 for calling the MLP obj's underlying member method code with example usage: obj.forward(x) and returns: x