old_contents: import os
  import fnmatch
  import restructuredtext_lint
  
  
  DEFAULTS = {
      'files': '*.rst',
  }
  
  
  def make_message(error):
      return '%s %s:%s %s\n' % (
          error.type, error.source, error.line, error.message,
      )
  
  
  def check(file_staged_for_commit, options):
      basename = os.path.basename(file_staged_for_commit.path)
      if not fnmatch.fnmatch(basename, options.rst_files):
          return True
      errors = restructuredtext_lint.lint(
          file_staged_for_commit.contents,
          file_staged_for_commit.path,
      )
      if errors:
          print('\n'.join(make_message(e) for e in errors))
          return False
      else:
          return True
  
new_contents: """Check that files contains valid ReStructuredText."""
  import os
  import fnmatch
  import restructuredtext_lint
  
  
  DEFAULTS = {
      'files': '*.rst',
  }
  
  
  def make_message(error):
      return '%s %s:%s %s\n' % (
          error.type, error.source, error.line, error.message,
      )
  
  
  def check(file_staged_for_commit, options):
      basename = os.path.basename(file_staged_for_commit.path)
      if not fnmatch.fnmatch(basename, options.rst_files):
          return True
      errors = restructuredtext_lint.lint(
          file_staged_for_commit.contents,
          file_staged_for_commit.path,
      )
      if errors:
          print('\n'.join(make_message(e) for e in errors))
          return False
      else:
          return True
  
subject: Add description to rst plugin