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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get(self, key, default=UndefinedKey):
 """Get a value from the tree :param key: key to use (dot separated). E.g., a.b.c :type key: basestring :param default: default value if key not found :type default: object :return: value in the tree located at key """

        return self._get(ConfigTree.parse_key(key), 0, default)