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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_dependencies(self, item):
 """ Performs a dependency check on the given item. :param item: Node to start the dependency check with. :return: The result on merged dependencies down the hierarchy. """

        def _get_sub_dependency(sub_item):
            e = self._deps.get(sub_item)
            if e is None:
                return self.get_default()

            if e.dependencies is NotInitialized:
                e.dependencies = self.merge_dependency(sub_item, _get_sub_dependency, e.parent)
            return e.dependencies

        return _get_sub_dependency(item)