code: def render_to_string(template_name, context=None, request=None, using=None):
      
      if isinstance(template_name, (list, tuple)):
          template = select_template(template_name, using=using)
      else:
          template = get_template(template_name, using=using)
      return template.render(context, request)
docs: Loads a template and renders it with a context. Returns a string.
      template_name may be a string or a list of strings.