I am pretty sure that I have implemented a lot of functions before that would be almost (or completely) identical (not including variable names, indentation, et

I am pretty sure that I have implemented a lot of functions before that would be almost (or completely) identical (not including variable names, indentation, etc.) to that of someone else's work. The smaller the function, the more likely it seems to be true, and some programming languages encourage you to write concise functions.