异常处理

异常处理:
    d = {'a': 2}
    try:
            d['c']
    except (KeyError, IndexError)  as e:
        print("not good key %s " % e)
    except IndexError  as e:
        print("not good key %s " % e)
    except Exception as e:  #抓住所有错误, 一般放在最后
        pass
    else:
        print("一切正常")
    finally:
        print("有没有错都执行")


自定义异常:
    raise


动态加载模块
    import importlib
    aa = importlib.import_module("lib.aa")
    print(aa.C().name)

断言
class ClassABC(object):
    def __init__(self, name):
        self.name = name

obj = ClassABC('hh')
assert type(obj.name) is str