Gets and sets the property SerialNumber. 
            
            The identification number of the MFA device that is associated with the IAM user who
            is      making the  CopyC# call. Specify this value if the IAM
            user has a policy      that requires MFA authentication. The value is either the serial
            number for a hardware device      (such as
CopyC# call. Specify this value if the IAM
            user has a policy      that requires MFA authentication. The value is either the serial
            number for a hardware device      (such as GetSessionToken
 CopyC#) or an Amazon
            Resource Name (ARN) for a virtual device      (such as
CopyC#) or an Amazon
            Resource Name (ARN) for a virtual device      (such as GAHT12345678
 CopyC#).
            You can find the device for an IAM      user by going to the AWS Management Console
            and viewing the user's security credentials.
CopyC#).
            You can find the device for an IAM      user by going to the AWS Management Console
            and viewing the user's security credentials. 
            arn:aws:iam::123456789012:mfa/user
 Declaration Syntax
 Declaration Syntax| C# | 
public string SerialNumber { get; set; }