docs: def _resolve_template(value, model_instance=None, context=None):
          """Resolves any template references in the given value."""
          if isinstance(value, string_types) and "{" in value:
              if context is None:
                  context = Context()
              if model_instance is not None:
                  context[model_instance._meta.model_name] = model_instance
              value = Template(value).render(context)
          return value