old_contents: # -*- encoding: utf-8
  """
  Git-related utilities used in our Travis scripts.
  """
  
  
  import subprocess
  import sys
  
  
  def git(*args):
      """Run a Git command and return its output."""
      cmd = ['git'] + list(args)
      try:
          return subprocess.check_output(cmd).decode('ascii').strip()
      except subprocess.CalledProcessError as err:
          print(err)
          sys.exit(err.returncode)
  
  
  # Root of the Git repository
  ROOT = git('rev-parse', '--show-toplevel')
  
  
  def get_changed_paths(*args):
      """
      Returns a set of changed paths in a given commit range.
  
      :param commit_range: Arguments to pass to ``git diff``.
      """
      files = set()
      diff_output = git('diff', '--name-only', *args)
  
      return set([
          line.strip()
          for line in diff_output.splitlines()
      ])
  
new_contents: # -*- encoding: utf-8
  """
  Git-related utilities used in our Travis scripts.
  """
  
  
  import subprocess
  import sys
  
  
  def git(*args):
      """Run a Git command and return its output."""
      cmd = ['git'] + list(args)
      try:
          return subprocess.check_output(cmd).decode('ascii').strip()
      except subprocess.CalledProcessError as err:
          print(err)
          sys.exit(err.returncode)
  
  
  # Root of the Git repository
  ROOT = git('rev-parse', '--show-toplevel')
  
  
  def get_changed_paths(*args):
      """
      Returns a set of changed paths in a given commit range.
  
      :param commit_range: Arguments to pass to ``git diff``.
      """
      diff_output = git('diff', '--name-only', *args)
  
      return set([
          line.strip()
          for line in diff_output.splitlines()
      ])
  
subject: remove an unused variable