def on_cleanup_error(function, path, excinfo):
                click.secho("warning: failed to remove file or directory: {}\n"
                            "please delete it manually.".format(path),
                            fg="red")
def find_files(pattern, root):
  """Return all the files matching pattern below root dir."""
  for path, _, files in os.walk(root):
    for filename in fnmatch.filter(files, pattern):
      yield os.path.join(path, filename)