code: def model(self, x, t):
      cond = self.condition
      uncond = self.unconditional_condition
      if self.before_sample is not None:
          x, t, cond, uncond = self.before_sample(x, t, cond, uncond)
      res = self.model_fn_(x, t, cond, uncond)
      if self.after_sample is not None:
          x, t, cond, uncond, res = self.after_sample(
              x, t, cond, uncond, res
          )
  
      if isinstance(res, tuple):
          # (None, pred_x0)
          res = res[1]
  
      return res
  
imports: import torch
  import math
  import tqdm
label_desc: Use image node_id 3 for calling the UniPC obj's underlying member method code with example usage: obj.model(x, t) and returns: res