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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 do_add_auth(self, params):
 """ \x1b[1mNAME\x1b[0m add_auth - Authenticates the session \x1b[1mSYNOPSIS\x1b[0m add_auth <scheme> <credential> \x1b[1mEXAMPLES\x1b[0m > add_auth digest super:s3cr3t """

        self._zk.add_auth(params.scheme, params.credential)