new_contents: #!/usr/bin/env python
  
  # Copyright 2018 The Kubernetes Authors.
  #
  # 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.
  
  """Executes a command, afterwards executes coalesce.py, preserving the return code.
  
  Also supports configuring bazel remote caching."""
  
  import argparse
  import os
  import subprocess
  import sys
  
  ORIG_CWD = os.getcwd()
  
  def test_infra(*paths):
      """Return path relative to root of test-infra repo."""
      return os.path.join(ORIG_CWD, os.path.dirname(__file__), '..', *paths)
  
  def check(*cmd):
      """Log and run the command, raising on errors."""
      print >>sys.stderr, 'Run:', cmd
      subprocess.check_call(cmd)
  
  def call(*cmd):
      """Log and run the command, raising on errors."""
      print >>sys.stderr, 'Run:', cmd
      return subprocess.call(cmd)
  
  
  def main(cmd):
      """Run script and preserve return code after running coalesce.py."""
      if not cmd:
          raise ValueError(cmd)
      # update bazel caching configuration if enabled
      if os.environ.get('BAZEL_REMOTE_CACHE_ENABLED', 'false') == 'true':
          print 'Bazel remote cache is enabled, generating .bazelrcs ...'
          # TODO(bentheelder): consider moving this once we've migrated all users
          # of the remote cache to this script
          check(test_infra('images/bootstrap/create_bazel_cache_rcs.sh'))
      # call the user supplied command
      return_code = call(*cmd)
      # Coalesce test results into one file for upload.
      check(test_infra('hack/coalesce.py'))
      # preserve the exit code
      sys.exit(return_code)
  
  
  if __name__ == '__main__':
      PARSER = argparse.ArgumentParser()
      PARSER.add_argument('cmd', nargs=1)
      PARSER.add_argument('args', nargs='*')
      ARGS = PARSER.parse_args()
      main(ARGS.cmd + ARGS.args)
  
subject: introduce execute_bazel scenario