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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 _overwrite(self, n):
 """Overwrite old file with new and keep file with suffix .old """

        if os.path.isfile(n[:-4]):
            shutil.copy2(n[:-4], n[:-4] + ".old")
            print("Old file {0} saved as {1}.old".format(
                n[:-4].split("/")[-1], n[:-4].split("/")[-1]))
        if os.path.isfile(n):
            shutil.move(n, n[:-4])
            print("New file {0} overwrite as {1}".format(
                n.split("/")[-1], n[:-4].split("/")[-1]))