def register_rds_db_instance(StackId=None, RdsDbInstanceArn=None, DbUser=
    None, DbPassword=None):
    """
    Registers an Amazon RDS instance with a stack.
    See also: AWS API Documentation
    
    
    :example: response = client.register_rds_db_instance(
        StackId='string',
        RdsDbInstanceArn='string',
        DbUser='string',
        DbPassword='string'
    )
    
    
    :type StackId: string
    :param StackId: [REQUIRED]
            The stack ID.
            

    :type RdsDbInstanceArn: string
    :param RdsDbInstanceArn: [REQUIRED]
            The Amazon RDS instance's ARN.
            

    :type DbUser: string
    :param DbUser: [REQUIRED]
            The database's master user name.
            

    :type DbPassword: string
    :param DbPassword: [REQUIRED]
            The database password.
            

    """
    pass
