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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 mfa_status(self, mfa_status):
 """ Sets the mfa_status of this AccountInfo. The enforcement status of the multi-factor authentication, either 'enforced' or 'optional'. :param mfa_status: The mfa_status of this AccountInfo. :type: str """

        allowed_values = ["enforced", "optional"]
        if mfa_status not in allowed_values:
            raise ValueError(
                "Invalid value for `mfa_status` ({0}), must be one of {1}"
                .format(mfa_status, allowed_values)
            )

        self._mfa_status = mfa_status