code: def preprocess(lines, filename=None, cwd=None):
      if isinstance(lines, str):
          with _open_source(lines, filename) as (lines, filename):
              yield from preprocess(lines, filename)
          return
  
      # XXX actually preprocess...
      for lno, line in enumerate(lines, 1):
          kind = "source"
          data = line
          conditions = None
          yield _common.SourceLine(
              _common.FileInfo(filename, lno),
              kind,
              data,
              conditions,
          )
  
label_desc: Use image node_id 1 for calling a global function with example usage: preprocess(lines, filename, cwd) without return types