Object-oriented Programming (面向对象编程，对象英文名为object）is new fashion and proved to be
plausible in Nowadays Programming world.
In python, we have many data type,like int,float,string,bool,for every data type,we can
correspond method.Here is some example:
[1] a = "Hello human" #We assign the "Hello human"(string type) to variable a.
[2] '''For the object a,as for a string type,we have some method to deal with it.Maybe we want it
[3] appears to be in upper case?'''
[4] print(a.upper()）#Guess the result?-->the result is "HELLO HUMAN".
[5] b = 2 #Now we assign the 2(integer type) to variable b.
[6] print(b.upper()) #Guess the result?-->Python would throw out "AttributeError"
AttributeError means b has no attribute called "upper",that is,for the integer type,we have no
method called "upper" to change it case.And obviously, this only apply to string.
See you next time,we would talk about class substantially in the next text.