code: def rgb2gray(img):
      r, g, b = torch.split(img, 1, dim=1)
      return (
          torch.mul(r, 0.299)
          + torch.mul(g, 0.587)
          + torch.mul(b, 0.114)
      )
  
file_path: insightface/recognition/idmmd/utils.py
imports: import os
  import numpy
  import torch
  import torch.nn.functional
label_desc: Use image node_id 4 for calling a global function with example usage: rgb2gray(img) and returns: unknown