code: def resolve_model_op(self, opspec):
      path = os.path.join(config.cwd(), opspec)
      if not os.path.exists(path):
          return None
      if not util.is_executable_file(path):
          raise plugin.ModelOpResolutionError(
              "must be an executable file"
          )
      model = ExecScriptModelProxy(path, opspec)
      return model, model.op_name
  
file_path: guildai/guild/plugins/exec_script.py
imports: import os
  from guild import config
  from guild import guildfile
  from guild import model
  from guild import plugin
  from guild import util
label_desc: Use image node_id 1 for calling the ExecScriptPlugin obj's underlying member method code with example usage: obj.resolve_model_op(opspec) and returns: model,  model, None