code: def Opt(re):
      """
      Opt(re) is an RE which matches either |re| or the empty string.
      """
      result = Alt(re, Empty)
      result.str = "Opt(%s)" % re
      return result
  
imports: from __future__ import absolute_import
  import types
  from .None import Errors
label_desc: Use image node_id 12 for calling a global function with example usage: Opt(re) and returns: result