Pythonの例外処理を少し便利に ref: http://qiita.com/items/c39b462376a48eae3646

file0.txt

import functools

class MyException(Exception):
    def __init__(self, original, *args, **kwargs):
        super(MyException, self).__init__(str(original), *args, **kwargs)
        self.original = original

def raise_as(except_classes, target_class):
    def wrapper(f):
        @functools.wraps(f)
        def wrapper_inner(*args, **kwargs):
            try:
                return f(*args, **kwargs)
            except except_classes as e:
                raise target_class(e)
        return wrapper_inner
    return wrapper

@raise_as(IndexError, MyException)
def func(a):
    l = [1,2]
    return l[a]

file1.txt

func(3)  # MyException
func('hoge')  # TypeError

file2.txt

def try_return(except_classes, value=None):
    def wrapper(f):
        def wrapper_inner(*args, **kwargs):
            try:
                return f(*args, **kwargs)
            except except_classes:
                return value
        return wrapper_inner
    return wrapper

@try_return(ZeroDivisionError, None)
def func(x):
    return 1 / x

print func(1) # 1
print func(0) # None