Python中BaseException的子分类问题

我想创建自己的Python异常类,如下所示:

class MyException(BaseException):
    def __init__(self, errno, address):
        if errno == 10048:
            mess = str(address) + ' is already in use'
        else:
            mess = 'Unable to open ' + str(address)
        BaseException.__init__(mess)

BaseException.__init__()

BaseException.__init__(mess)
TypeError: descriptor '__init__' requires a 'exceptions.BaseException' object but received a 'str'

我认为BaseException可以接受任何一组参数。另外,我应该如何将“exceptions.BaseException”对象传递到exceptions.BaseException的构造函数中?