code: def conv1x1(in_planes, out_planes, stride=1):
      """helper function for constructing 1x1 convolution"""
      return nn.Conv2d(
          in_planes,
          out_planes,
          kernel_size=1,
          stride=stride,
          bias=False,
      )
  
imports: import copy
  import math
  import re
  import warnings
  from collections import OrderedDict
  from typing import Any, Dict, Optional, Sequence
  import torch.nn
  from classy_vision.generic.util import is_pos_int, is_pos_int_tuple
  from .None import register_model
  from .classy_model import ClassyModel
  from .squeeze_and_excitation_layer import SqueezeAndExcitationLayer
label_desc: Use image node_id 2 for calling a global function with example usage: conv1x1(in_planes, out_planes, stride) and returns: nn