code: def sde(self, x, t, y):
      drift = (
          0.5
          * self.stiffness
          * batch_broadcast(self._beta(t), y)
          * (y - x)
      )
      diffusion = torch.sqrt(self._beta(t))
      return drift, diffusion
  
imports: import abc
  import warnings
  import numpy
  import torch
label_desc: Use image node_id 5 for calling the OUVPSDE obj's underlying member method code with example usage: obj.sde(x, t, y) and returns: drift,  diffusion