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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_combo(self, symbol):
 """ get group by child symbol """

        for parent, legs in self.instrument_combos.items():
            if symbol == parent or symbol in legs.keys():
                return {
                    "parent": self.get_instrument(parent),
                    "legs": legs,
                }
        return {
            "parent": None,
            "legs": {},
        }