assigns the object on which the method was called to this self parameter so this is what happens herein line we create the object annesacc from the account class the object annesacc is linked to the account classwhich provides the three instance methods mentioned above in line we add an attribute called balance to the object annesaccand give it value of the attribute is only available in this particular objectnot to the account class or any other objects which we might create from the account class later on in line we call an instance method of the object annesacc the object was created from the account classso we look for the method being called in this class the method was defined as deposit(selfamount)but we pass just one parameter when calling it (amountpython automatically associates the annesacc object with the parameter selfand we only need to provide the parameters from the second one in the parameter list on inside the deposit methodwe have access to the object on which it was called (annesaccvia the self variableand can modify the balance attribute of this object classes can have attributestoo we already know that classes are some kind of objectstoo instances link to the class object of the class from which they were createdso for example we can use the deposit(selfamountmethod of the account class to modify any instance created from the account class class object can also have attributeswhich we call class attributes in the following examplethe account class has class attribute called num of accountswhich records how many accounts were created so what exactly happens herein line we create the class attribute by assigning variable called num of accounts in the namespace of the account class note that the class variable has the same indent as the methods we defined within the class at the time when the class object is createdthe initial value for the class attribute is set to in the constructor methodwe modify the num of accounts class attribute recall that the init method is called each time when an instance object is created from the class each time this happenswe increment the num of accounts class attribute we access the class attribute by using the class name together with the dot notationaccount num of accounts (as shown in lines and annemarie friedrichcis lmu munchenws /