What does [, element] mean?
python
Solution
The Python documentation has a section about the used notation, which says:
[…] a phrase enclosed in square brackets (`[ ]`) means zero or one occurrences (in other words, the enclosed phrase is optional).
This notation originates from the Backus–Naur Form (BNF).
Problem
I was reading the python documentation where I came across `elem [,n]` this notation for arguments. I have seen such notations in past. Don't just know what they mean. Also, google doesn't support searching brackets.