are numeric types passed by value or reference?

[rudihammad]

Hello,
I would like to know if python passed certain data types by value, and other data types by reference.
Here is an example:

def multiply(myArg):
    myArg = myArg * 2
    return myArg   
y = 5    
multiply(y)
print y # Result is 5, so the variable Y was passed by value?



def appendToList(myList):
    myList.append("luululu")
    
someList = list()    
appendToList(someList)
print someList # Result: ['luululu'], so it was passed by reference?

As you can see the variable y was not modified, whereas the list was modified. So are numeric types passed by value and lists, tuples and other objects passed by reference?

Thank you