How to print error ??

Couple of options. If you want to display some custom error message, you can try to replace Errors with the message (works for text type fields).

Or use error handling on the column that has errors. Here's how:

Add custom column to your data, use try (all lowercase) and pass it the column name that has errors. Expand this custom column to get the Error. And then expand the Error column further to get the reason and details.

Hope this helps.

Thanks,

Tarun