code: def fetch_node_from(self, path):
          
          context = self
          for key in path:
              context = context[key]
              if context is None:
                  break
          return context
docs: Returns a node for a path.
  
          :param path: Tuple of :term:`hashable` s.
          :rtype: :class:`~cerberus.errors.ErrorTreeNode` or :obj:`None`