Beware of bugs in the above code; I have only proved it correct, not tried it.
Every book has mistakes in them, every one. There's never been a book published without mistakes.
Never test for an error condition you don't know how to handle.
On two occasions I have been asked, 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.
Your credit report should be 100% accurate, so make sure everything is entirely correct. If something doesn't look right, dispute it.
You can't put rubbish into a computer and get something good out.
Although no one loves a typo, it's close to impossible to eradicate every single little mistake in a manuscript.
Engineers are not superhuman. They make mistakes in their assumptions, in their calculations, in their conclusions. That they make mistakes is forgivable; that they catch them is imperative. Thus it is the essence of modern engineering not only to be able to check one's own work but also to have one's work checked and to be able to check the work of others.
Proofread carefully to see if you any words out.
If any sort of error is inexcusable, it's an incorrect phone number. One of the cardinal rules of copy editing is that every phone number published must be checked.