pythonScope errorMedium

The list that remembers

Time: 0:00

What it should do

append_to_list(val) should create a new list with val if no list is provided. test_append() calls it twice with 1 and 2.

What goes wrong

test_append() returns [[1, 2], [1, 2]] because both calls share the same list in memory.

Hints

This is a scope and closure bugs bug

Every callback reports the last value, a counter never increments, UnboundLocalError on a variable you can see.