code: def annotate(node):
      
      tb = sys.exc_info()[2]
      while tb and stack_bottom not in tb.tb_frame.f_locals:
          tb = tb.tb_next
      if not tb:
          # We did not find any exec of an SConscript file: what?!
          raise SCons.Errors.InternalError("could not find SConscript stack frame")
      node.creator = traceback.extract_stack(tb)[0]
docs: Annotate a node with the stack frame describing the
      SConscript file and line number that created it.