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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 edit(self):

 """
 Edit file with default os application.
 """

        if platform.system().lower() == 'windows':
            os.startfile(str(self.config_file))
        else:
            if platform.system().lower() == 'darwin':
                call = 'open'
            else:
                call = 'xdg-open'
            subprocess.call([call, self.config_file])