code: def forward(self, x):
      x = self.flatten(x)
      x = self.sequential_1(x)
      return x
  
imports: from multiprocessing import Process
  import time
  from typing import List
  import unittest
  import numpy
  import pandas
  import os
  from bigdl.ppml.fl import *
  from bigdl.ppml.fl.nn.fl_server import FLServer
  from bigdl.ppml.fl.nn.fl_context import init_fl_context
  from bigdl.ppml.fl.estimator import Estimator
  from torch import Tensor, nn
  import torch
  from torch.utils.data import DataLoader
  from torchvision import datasets
  from torchvision.transforms import ToTensor
  from bigdl.ppml.fl.utils import FLTest
  import shutil
label_desc: Use image node_id 2 for calling the NeuralNetworkPart1 obj's underlying member method code with example usage: obj.forward(x) and returns: x