range_python_2.py

def range(x, y=None):
    results = []
    if y is None:
        y = x
        x = 0
    while x < y:
        results.append(x)
        x += 1
    return results


# Tests ;)
assert range(5) == [0, 1, 2, 3, 4]
assert range(2, 10) == [2, 3, 4, 5, 6, 7, 8, 9]