[Python 06] 抽象

--------67.py-----------#!/usr/bin/python# filename : intervaldef interval(start, stop = None, step = 1) :    if stop is None :         stop = 10    result = []    i = start    while i < stop :        result.append(i)        i += step    print result    return resultinterval(1)interval(1, 5)interval(2, 20, 3)慎重使用全局变量