Why this code needs square bracket ?

Question

In line 7 it seems to have square bracket , why ??
why max and min doesn't need but sum needs it ?
https://code.sololearn.com/c3W1YtbchZs5/?ref=app

Answer 1

take a look at the min/max and sum functions in this page:
https://docs.python.org/3/library/functions.html
sum takes two arguments at most
first one is an iterable (list, tuple, etc...) and initial value
min/max however is more flexible than that
it can either take in an iterable, or two or more arguments