def OmahaTagExe(env, target, source, tag):
  """Tags an EXE using ApplyTag.

  Args:
    env: The environment.
    target: Name of the tagged file.
    source: Name of the file to be tagged.
    tag: Tag to be applied.

  Returns:
    Output node list from env.Command().
  """

  tag_exe = '$MAIN_DIR/internal/tools/ApplyTag.exe'
  tag_cmd = env.Command(
      target=target,
      source=source,
      action=tag_exe + ' $SOURCES $TARGET ' +
      '%s append' % tag,
  )

  return tag_cmd