old_contents: """Markdown template filter."""
  
  from django import template
  from django.template.defaultfilters import stringfilter
  
  import bleach
  import markdown
  
  register = template.Library()
  
  
  @register.filter(is_safe=True, name='markdown')
  @stringfilter
  def markdown_filter(value):
      """Convert markdown value to html."""
      return bleach.clean(markdown.markdown(value))
  
new_contents: """Markdown template filter."""
  
  from django import template
  
  import bleach
  import markdown
  
  register = template.Library()
  
  
  @register.filter(name='markdown', is_safe=True)
  def markdown_filter(value):
      """Convert markdown value to html."""
      return bleach.clean(markdown.markdown(value))
  
subject: remove stringfilter