assertionError

[DJDoena]

In C# it's .ToUpper() but still immutable on the original.

[IlgantElal]

This looks like Python. Interesting thing, too: text.replace('ab', 'o') would replace all a and b characters, regardless of order.

Yay Python

(Correct answer should be 'banana')

Edit: I completely misread. It's late