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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_file_lines(self, subsystem, option):
 """ Read the lines of the given file from the given subsystem. Do not include the subsystem name in the option name. Only call this method if the given subsystem is available. """

        assert subsystem in self
        with open(os.path.join(self.per_subsystem[subsystem], subsystem + '.' + option)) as f:
            for line in f:
                yield line