class_dict_add_attr.py

from __future__ import print_function

class Attribute(object):
    def __init__(self):
        pass

def main():
    a = Attribute();
    print(a.__dict__)
    a.__setattr__("test", 5)
    print(a.__dict__)
    print(a.test)

if __name__ == '__main__':
    main()

python_practice.py

from __future__ import print_function

class Attribute(object):
    def __init__(self):
        object.__setattr__(self, "attr", {"a": "123", "b": "456", "c": 5})

    def __setattr__(self, name, value):
        if name in self.attr:
            self.attr[name] = value
            return

        raise AttributeError

    def __getattr__(self, name):
        if name in self.attr:
            return self.attr[name]

        raise AttributeError

    def __repr__(self):
        return str(self.attr)

    def __str__(self):
        return self.__repr__()

    def set_attributes(self, **args):
        #for k, v in args.items():
            #print(k, v)
        self.attr.update(args)


def main():
    x = Attribute()
    x.a = 5
    x.c = 6
    x.set_attributes(d=7, aaa=15, eee=8)

    print(x)
    print(x.a)
    print(x.b)
    print(x.c)
    print(x.d)
    print(x.aaa)
    print(x.eee)

if __name__ == '__main__':
    main()