内部对象-特殊属性

class A:
    def __init__(self):
        print('this is __init__ function')
    def __str__(self):
        print('this is __str__ function')
"""类、函数、方法、描述器或生成器实例的名称"""
print(A.__name__)  # A
"""类实例所属的类"""
print(A().__class__)  # <class '__main__.A'>
"""由类对象的基类所组成的元组"""
print(A.__bases__)  # (<class 'object'>,)
"""一个字典或其他类型的映射对象，用于存储对象的（可写）属性"""
print(A.__dict__)
# {'__module__': '__main__', '__init__': <function A.__init__ at 0x7f95b020db00>, 
# '__str__': <function A.__str__ at 0x7f95a0035170>, '__dict__': <attribute '__dict__' of 'A' objects>, 
# '__weakref__': <attribute '__weakref__' of 'A' objects>, '__doc__': None}