Determines whether Python is call-by-value, call-by-reference, or call-by-sharing

callby.py

arg = {'x': 0}

def f(param):
    same_ids = id(arg) == id(param)
    different_ids = not same_ids
    param = {'y': 4}
    arg_changed = 'y' in arg
    print('Call by value: {}'.format(different_ids))
    print('Call by sharing: {}'.format(same_ids and not arg_changed))
    print('Call by reference: {}'.format(same_ids and arg_changed))

f(arg)