Return the “identity” of an object. This is an integer which is guaranteed to be unique and constant for this object during its lifetime. Two objects with non-overlapping lifetimes may have the same id() value.
CPython implementation detail: This is the address of the object in memory.
说明：
1. 返回对象的唯一标识符，用整数表示。在程序生命周期内，这个标识符常量是唯一的。
>>> a = 1
>>> id(a)
1652447504
>>> id(1.0)
66116592
>>> a = ‘some text‘
>>> id(a)
69228568
