Another developer claims that certain fragment of my code has been "copy-pasted from the web". This is simply not correct, I wrote the code myself and understand it well. The code also works as expected.
How to respond in a professional way to such a claim? Do I need to respond differently if the claim has been repeated for the second or third time? This probably should be some short reply, putting the burden of evidence on the person who raises the claim, not on me.
Let's assume that the code itself is fine, not copy-pasted. The words come from my supervisor but I am convinced he just rephrases claims of the known another person more or less of my level in the hierarchy.
There is a question disciplinary infraction but seems not applicable for my case. I really have no idea how to provide "emails, written documents, and find people who will be able to back up your story" that I has been sitting and writing this code myself.