code: def transform(self, x):
      assert isinstance(x, torch.Tensor)
      # Handle grayscale, tile 3 times
      if x.size(0) == 1:
          x = torch.cat([x] * 3, dim=0)
      return x
  
imports: import collections
  import math
  import random
  import warnings
  import torch
  from mmf.common.constants import INCEPTION_IMAGE_NORMALIZE
  from mmf.common.registry import registry
  from mmf.datasets.processors.processors import BaseProcessor
  from omegaconf import OmegaConf
  from torchvision import transforms
  from torchvision.transforms import Compose, Normalize, Resize, ToTensor
label_desc: Use image node_id 3 for calling the GrayScaleTo3Channels obj's underlying member method code with example usage: obj.transform(x) and returns: x