System.Net.ValidationHelper.MakeStringNull C# (CSharp) Method

        public static string MakeStringNull(string stringValue) {
            if ( stringValue == null || stringValue.Length == 0) {
                return null;
            } else {
                return stringValue;
            }
        }

 internal Authorization(string token, bool finished, string connectionGroupId, bool mutualAuth)
 {
     this.m_Message           = ValidationHelper.MakeStringNull(token);
     this.m_ConnectionGroupId = ValidationHelper.MakeStringNull(connectionGroupId);
     this.m_Complete          = finished;
     this.m_MutualAuth        = mutualAuth;
 }