<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def fetch_node_from(self, path):
 """ Returns a node for a path. :param path: Tuple of :term:`hashable` s. :rtype: :class:`~cerberus.errors.ErrorTreeNode` or :obj:`None` """

        context = self
        for key in path:
            context = context[key]
            if context is None:
                break
        return context