code: private void verifyPathIsOEX(File path) {
      checkNotNull(path);
      checkArgument(path.exists(), "%s does not exist", path.getAbsolutePath());
      checkArgument(!path.isDirectory(), "%s is a directory", path.getAbsolutePath());
      checkArgument(path.getName().endsWith(".oex"), "%s does not end with .oex", path.getName());
    }
docs: Verify that the given path exists and is an OEX file.