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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 save_state(self):
 """Save current state of GUI to configuration file."""

        set_setting('lastSourceDir', self.source_directory.text())
        set_setting('lastOutputDir', self.output_directory.text())
        set_setting(
            'useDefaultOutputDir', self.scenario_directory_radio.isChecked())