old_contents: from __future__ import absolute_import
  import os
  import nox
  
  BLACK_PATHS = ["iam_groups_authn"]
  
  if os.path.exists("samples"):
      BLACK_PATHS.append("samples")
  
  
  @nox.session
  def lint(session):
      """Run linters.
      Returns a failure if the linters find linting errors or sufficiently
      serious code quality issues.
      """
      session.install("-r", "requirements-test.txt")
      session.install("-r", "requirements.txt")
      session.run("black", "--check", *BLACK_PATHS)
  
new_contents: # Copyright 2022 Google LLC
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #      http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from __future__ import absolute_import
  import os
  import nox
  
  BLACK_PATHS = ["iam_groups_authn"]
  
  if os.path.exists("samples"):
      BLACK_PATHS.append("samples")
  
  
  @nox.session
  def lint(session):
      """Run linters.
      Returns a failure if the linters find linting errors or sufficiently
      serious code quality issues.
      """
      session.install("-r", "requirements-test.txt")
      session.install("-r", "requirements.txt")
      session.run("black", "--check", *BLACK_PATHS)
  
subject: add header