code: def multistep_uni_pc_update(
      self, x, model_prev_list, t_prev_list, t, order, **kwargs
  ):
      if len(t.shape) == 0:
          t = t.view(-1)
      if "bh" in self.variant:
          return self.multistep_uni_pc_bh_update(
              x, model_prev_list, t_prev_list, t, order, **kwargs
          )
      else:
          assert self.variant == "vary_coeff"
          return self.multistep_uni_pc_vary_update(
              x, model_prev_list, t_prev_list, t, order, **kwargs
          )
  
imports: import torch
  import math
  import tqdm
label_desc: Use image node_id 10 for calling the UniPC obj's underlying member method code with example usage: obj.multistep_uni_pc_update(x, model_prev_list, t_prev_list, t, order) and returns: self, self