code: def E4():
      def diffeq(t, y):
          dy0 = y[1]
          dy1 = 0.32 - 0.4 * y[1] ** 2
          return torch.stack([dy0, dy1])
  
      def init():
          return torch.tensor(0.0), torch.tensor([30.0, 0.0])
  
      return diffeq, init, None
  
imports: import math
  import torch
label_desc: Use image node_id 20 for calling a global function with example usage: E4() and returns: diffeq,  init,  None, torch, torch,  torch