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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 enable_mfa_device(self, user_name, serial_number, authentication_code_1, authentication_code_2):
 """Enable MFA Device for user."""

        user = self.get_user(user_name)
        if serial_number in user.mfa_devices:
            raise IAMConflictException(
                "EntityAlreadyExists",
                "Device {0} already exists".format(serial_number)
            )

        user.enable_mfa_device(
            serial_number,
            authentication_code_1,
            authentication_code_2
        )