Python's mutable default data types When I first started learning programming (using python), I loved how explicit things were. a=5 assigns the value 5 to the variable a, b = [1,2,3] creates a list with 1,2,3 and assigns it to the variable b. Pretty quickly, you want to create a new list based on an old list. So you might naturally search for "adding an item to a list in python" and come accross the .
