Why do you need double Parenthesis when appending to a list

Learning Python 3
Python Gradebook exercise

I am just wondering why you need to have double parenthesis when appending to a more than one value at a time.

example: gradebook.append((‘visual arts’, 93))

When I append without the double parenthesis, I get:
TypeError: append() takes exactly one argument (2 given)

I get what the error is saying, I just don’t understand why adding the extra parenthesis around the values I’m trying to pass to the list solves the problem.

Thanks ahead of time for the explanation


the append method can only append one item at a time, by using using an additional set of parentheses you append one tuple (tuple is an immutable list)

if you want to add multiple elements at once, use list extending:

lst = [1, 2, 3,]
lst += [4, 5, 6]