code: def save_knn_func(self, filename):
      self.knn_func.save(filename)
  
imports: import numpy
  import torch
  from ..distances import BatchedDistance, CosineSimilarity
  from .None import common_functions
label_desc: Use image node_id 10 for calling the InferenceModel obj's underlying member method code with example usage: obj.save_knn_func(filename) without return types