code: def _rgb_to_y(r: Tensor, g: Tensor, b: Tensor) -> Tensor:
      y: Tensor = 0.299 * r + 0.587 * g + 0.114 * b
      return y
  
file_path: kornia/kornia/color/ycbcr.py
imports: import torch
  from torch import Tensor, nn
label_desc: Use image node_id 1 for calling a global function with example usage: _rgb_to_y(r, g, b) and returns: y