code: def markdown(value, arg=None):
      
      extensions = (arg and arg.split(',')) or settings.MARKDOWN_EXTENSIONS
      return _markdown(value, extensions=extensions, safe=False)
docs: Render markdown over a given value, optionally using varios extensions.
  
      Default extensions could be defined which MARKDOWN_EXTENSIONS option.
  
      Syntax: ::
  
          {{value|markdown}}
  
          {{value|markdown:"tables,codehilite"}}
  
      :returns: A rendered markdown