code: def eval_codec(q, xb):
      codes = q.compute_codes(xb)
      decoded = q.decode(codes)
      return ((xb - decoded) ** 2).sum()
  
imports: import numpy
  import faiss
  import unittest
  from faiss.contrib import datasets
label_desc: Use image node_id 8 for calling a global function with example usage: eval_codec(q, xb) and returns: unknown