code: def onlyExisting(func):
      """Returns a filter func that when called with a list,
      only calls func on the non-NotImplemented items of the list,
      and only so if there's at least one item remaining.
      Otherwise returns NotImplemented."""
  
      def wrapper(lst):
          items = [item for item in lst if item is not NotImplemented]
          return func(items) if items else NotImplemented
  
      return wrapper
  
imports: from fontTools.misc.timeTools import timestampNow
  from fontTools.ttLib.tables.DefaultTable import DefaultTable
  from functools import reduce
  import operator
  import logging
label_desc: Use image node_id 8 for calling a global function with example usage: onlyExisting(func) and returns: wrapper, unknown