For example, if your string contains both 1 and 0, and you replace 1 with I, that might create a situation where another part of the string (e.g., something containing 10) is now altered in an unexpected way when 0 is replaced with O.

gangsta paradise

Why stopping at that function? Remove all built-in functions and use the bare language lol

well, wrote it in my text editor and comment # my solution.