Revert "changes for testing new functionality"

This reverts commit b207d417a7d3500e1193a534e62274ac0fe3535a.
Revert "Revert "added null check in toString""

This reverts commit 44e31529e53e84c9629cab7be23093a241da6431.
Revert "Revert "removed null check from rowToString""

This reverts commit d83c83c2b1981a72402fea329a53d8cde208ad20.
Revert "Revert "changed comment for another commit""

This reverts commit 414efe814972c9c587309b9e2579aa900a1239c8.
Revert "changed comment for another commit"

This reverts commit b84dce172eef402942a91a62740f542cbc74960d.
Revert "removed null check from rowToString"

This reverts commit 0503095b786e41eeeec68f2fd05790d166e98c14.
Revert "added null check in toString"

This reverts commit 0192df473e64d8d49a241f7a6413687f0d94d191.
adding missing null example