Tuples are initiated as :
a = () a = (1,2,"Hello World!") print a print a print a
(1, 2, 'Hello World!')
Yes, it is nearly the same as list and we can use len and slice functions here also but it is immutable. Let's try this:
a = () a = (1,2,"Hello World!") a  = 5
TypeError: 'tuple' object does not support item assignment
This is the same error that you had got while trying to change the elements of a string. Since tuple is also not mutable like string, so we can't change the elements of a tuple.
We also can't use append on tuples.
Don't worry about failure. You only have to right once.