Pickle translates almost any type of object into a string. pickle.dumps takes an object as a parameter and returns a string representation.
Although the new object has same value as the old, it is not the same object. In other words, pickling and then unpickling has the same effect as copying the object.
from Thinking in Python
原文：http://www.cnblogs.com/ryansunyu/p/3989463.html