old_contents: import re
  import percy
  
  class UserAgent(object):
  
      def __init__(self, config, environment):
        self.config = config
        self.environment = environment
  
      def __str__(self):
          client = ' '.join(filter(None, [
            "Percy/%s" % self._api_version(),
            "python-percy-client/%s" % self._client_version(),
          ]))
  
          environment = '; '.join(filter(None, [
            self._environment_info(),
            "python/%s" % self._python_version(),
            self.environment.current_ci,
          ]))
  
          return "%s (%s)" % (client, environment)
  
      def _client_version(self):
          return percy.__version__
  
      def _python_version(self):
          try:
              from platform import python_version
              return python_version()
          except ImportError:
              return 'unknown'
  
      def _django_version(self):
          try:
              import django
              return "django/%s" % django.get_version()
          except ImportError:
              return None
  
      def _api_version(self):
          return re.search('\w+$', self.config.api_url).group(0)
  
      def _environment_info(self):
          # we only detect django right now others could be added
          return self._django_version()
  
new_contents: import re
  import percy
  
  class UserAgent(object):
  
      def __init__(self, config, environment):
        self.config = config
        self.environment = environment
  
      def __str__(self):
          client = ' '.join(filter(None, [
            "Percy/%s" % self._api_version(),
            "python-percy-client/%s" % self._client_version(),
          ]))
  
          environment = '; '.join(filter(None, [
            self._environment_info(),
            "python/%s" % self._python_version(),
            self.environment.current_ci,
          ]))
  
          return "%s (%s)" % (client, environment)
  
      def _client_version(self):
          return percy.__version__
  
      def _python_version(self):
          try:
              from platform import python_version
              return python_version()
          except ImportError:
              return 'unknown'
  
      def _django_version(self):
          try:
              import django
              return "django/%s" % django.get_version()
          except ImportError:
              return None
  
      def _api_version(self):
          return re.search(r'\w+$', self.config.api_url).group(0)
  
      def _environment_info(self):
          # we only detect django right now others could be added
          return self._django_version()
  
subject: Fix invalid escape sequence (#33)