old_contents: from django.template.loader_tags import register
  from django.template import loader, Context, defaultfilters, TemplateDoesNotExist
  
  import markdown
  
  
  presenters = {
      'Speaker': 'presenters/speaker_presenter.html'
  }
  generic_template = 'presenters/object_presenter.html'
  
  
  @register.simple_tag(takes_context=True)
  def present(context, obj):
      model_name = type(obj).__name__
      template_name = presenters.get(model_name, generic_template)
  
      t = loader.get_template(template_name)
      return t.render(Context({
          'model_name': model_name,
          'obj': obj,
      }))
  
  
  @register.filter
  def noval(data, placeholder):
      if data:
          return data
  
      return placeholder
  
  
  @register.simple_tag(takes_context=True)
  def include_md(context, template_name):
      lang = context['LANGUAGE_CODE'].replace('-', '_')
      try:
          t = loader.render_to_string('markdown/{}/{}'.format(lang, template_name), context)
      except TemplateDoesNotExist:
          t = loader.render_to_string('markdown/en_US/{}'.format(template_name), context)
  
      html = markdown.markdown(t)
  
      return defaultfilters.safe(html)
  
new_contents: from django.template.loader_tags import register
  from django.template import loader, Context, defaultfilters, TemplateDoesNotExist
  
  import markdown
  
  
  presenters = {
      'Speaker': 'presenters/speaker_presenter.html'
  }
  generic_template = 'presenters/object_presenter.html'
  
  
  @register.simple_tag(takes_context=True)
  def present(context, obj):
      model_name = type(obj).__name__
      template_name = presenters.get(model_name, generic_template)
  
      t = loader.get_template(template_name)
      return t.render(Context({
          'model_name': model_name,
          'obj': obj,
      }))
  
  
  @register.filter
  def noval(data, placeholder):
      if data:
          return data
  
      return placeholder
  
  
  @register.simple_tag(takes_context=True)
  def include_md(context, template_name):
      lang = context['LANGUAGE_CODE'].replace('-', '_')
  
      try:
          t = loader.render_to_string('markdown/{}/{}'.format(lang, template_name), context)
      except TemplateDoesNotExist:
          t = loader.render_to_string('markdown/en/{}'.format(template_name), context)
  
      html = markdown.markdown(t)
  
      return defaultfilters.safe(html)
  
subject: Fix a bug in the template tag.