code: def bulk_impl(metric):
      """
      Decorator to register a bulk implementation for a metric.
      """
  
      def wrap(impl):
          metric.bulk_score = impl
          return impl
  
      return wrap
  
file_path: lkpy/lenskit/metrics/topn.py
imports: import logging
  import warnings
  import numpy
  import pandas
label_desc: Use image node_id 1 for calling a global function with example usage: bulk_impl(metric) and returns: wrap, impl