docs: def scope(self, key, *tags, default=None):
          """Only apply tags and default for top-level key, effectively scoping the tags."""
          scope = self._scopes[key]
          tags = self._ensure_exclamation(tags)
          default = default if not default or default.startswith("!") else "!" + default
  
          if scope:
              scope[0] = scope[0] + tags
              scope[1] = default if default else scope[1]
          else:
              scope.append(tags)
              scope.append(default)