We are going to pass an entire list to a function.
In [1]: numbers
Out[1]: [10, 5, 3, 7, 4]
Defining a function which we going to pass the entire list to. This function multiplies each of the list's element by 2.
In [2]: def modify_elements(items):
...: for i in range(len(items)):
...: items[i] *= 2
...:
In [3]: modify_elements(numbers)
In [4]: numbers
Out[4]: [20, 10, 6, 14, 8]
In [5]:
Function modify_elemens' items parameter receives a reference to the original list, so the statement in the loop's suite modifies each element in the original list object.