@db_api.api_context_manager.reader
def _ensure_rc_cache(ctx):
 global _RC_CACHE
 if (_RC_CACHE is not None):
  return
 _RC_CACHE = rc_cache.ResourceClassCache(ctx)

@ db_api . api_context_manager . reader def _ensure_rc_cache ( ctx ) : global _RC_CACHE if ( _RC_CACHE is not None ) : return _RC_CACHE = rc_cache . ResourceClassCache ( ctx )
ensures that a singleton resource class cache has been created in the modules scope .