old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  from django import template
  from django.utils.html import mark_safe
  
  register = template.Library()
  
  from django.conf import settings
  import os, re
  
  rx = re.compile(r"^(.*)\.(.*?)$")
  
  @register.simple_tag
  def version(path):
      full_path = os.path.join(settings.STATIC_ROOT, path)
      if not settings.DEBUG:
          # Get file modification time.
          os.stat_float_times(False)
          mtime = os.path.getmtime(full_path)  # raises OSError if file does not exist
          path = rx.sub(r"\1.%d.\2" % mtime, path)
  
      return os.path.join(settings.STATIC_URL, path)
  
  @register.filter
  def highlight(text, word):
      return mark_safe(text.replace(word, "<span class='highlight'>%s</span>" % word))
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  from django import template
  from django.utils.html import mark_safe
  
  register = template.Library()
  
  from django.conf import settings
  import os, re
  
  rx = re.compile(r"^(.*)\.(.*?)$")
  
  @register.simple_tag
  def version(path):
      full_path = os.path.join(settings.STATIC_ROOT, path)
      if not settings.DEBUG:
          # Get file modification time.
          os.stat_float_times(False)
          mtime = os.path.getmtime(full_path)  # raises OSError if file does not exist
          path = rx.sub(r"\1.{}.\2".format(mtime), path)
  
      return os.path.join(settings.STATIC_URL, path)
  
  @register.filter
  def highlight(text, word):
      return mark_safe(text.replace(word, "<span class='highlight'>%s</span>" % word))
  
subject: Use format() instead of %