code: def main(config_file):
      
  
      if not (os.path.exists(config_file) and os.path.isfile(config_file)):
          msg = "Missing or invalid config file {0}".format(config_file)
          raise ValueError(msg)
  
      print("Loading config file {0}.".format(config_file))
  
      # Use the appropriate network driver to connect to the device:
      driver = napalm.get_network_driver("eos")
  
      # Connect:
      device = driver(
          hostname="127.0.0.1",
          username="vagrant",
          password="vagrant",
          optional_args={"port": 12443},
      )
  
      print("Opening ...")
      device.open()
  
      print("Loading replacement candidate ...")
      device.load_replace_candidate(filename=config_file)
  
      # Note that the changes have not been applied yet. Before applying
      # the configuration you can check the changes:
      print("\nDiff:")
      print(device.compare_config())
  
      # You can commit or discard the candidate changes.
      try:
          choice = raw_input("\nWould you like to commit these changes? [yN]: ")
      except NameError:
          choice = input("\nWould you like to commit these changes? [yN]: ")
      if choice == "y":
          print("Committing ...")
          device.commit_config()
      else:
          print("Discarding ...")
          device.discard_config()
  
      # close the session with the device.
      device.close()
      print("Done.")
docs: Load a config for the device.