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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 _nested_relations(self, relation):
 """ Get the deeply nested relations for a given top-level relation. :rtype: dict """

        nested = {}

        for name, constraints in self._eager_load.items():
            if self._is_nested(name, relation):
                nested[name[len(relation + ".") :]] = constraints

        return nested