code: def gram_matrix(y):
      (b, ch, h, w) = y.size()
      features = y.view(b, ch, w * h)
      features_t = features.transpose(1, 2)
      gram = features.bmm(features_t) / (ch * h * w)
      return gram
  
imports: from PIL import Image
label_desc: Use image node_id 3 for calling a global function with example usage: gram_matrix(y) and returns: gram