@author jackzhenguo
@desc 
@date 2019/3/10

>>> class Student():
    def __init__(self,id,name):
        self.id = id
        self.name = name
    def __repr__(self):
        return 'id = '+self.id +', name = '+self.name

>>> xiaoming = Student(id='1',name='xiaoming')
>>> xiaoming
id = 1, name = xiaoming
>>> ascii(xiaoming)
'id = 1, name = xiaoming'

In [1]: delattr(xiaoming,'id')

In [2]: hasattr(xiaoming,'id')
Out[2]: False