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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 add_instruments(self, *instruments):
 """ add instruments after initialization """

        for instrument in instruments:
            if isinstance(instrument, ezibpy.utils.Contract):
                instrument = self.ibConn.contract_to_tuple(instrument)
                contractString = self.ibConn.contractString(instrument)
                self.instruments[contractString] = instrument
                self.ibConn.createContract(instrument)

        self.symbols = list(self.instruments.keys())