code: def _python_script_for_opdef_main(opdef):
      assert opdef.main, opdef
      main_mod = op_util.split_cmd(opdef.main)[0]
      model_paths = op_util.opdef_model_paths(opdef)
      try:
          _path, mod_path = python_util.find_module(
              main_mod, model_paths
          )
      except ImportError:
          return None
      try:
          return python_util.Script(mod_path)
      except SyntaxError:
          return None
  
imports: import os
  import re
  from guild import config
  from guild import op_util
  from guild import plugin
  from guild import python_util
  from guild import summary
  from .python_script import PythonScriptModelProxy
  from .python_script import PythonScriptOpdefSupport
label_desc: Use image node_id 6 for calling a global function with example usage: _python_script_for_opdef_main(opdef) and returns: python_util, None, None