My apologies, I feel really dumb.

I've updated the random test cases to match the JavaScript version.

Hi there.

I've updated the argument names to be like the others. The example test cases also make use of those from the example given.

My random tests made differ as I give a log of the letter to be replaced, it's frequency and the input strng. I;m happy to remove the detail or change the way the words are generated.

Happy to make any changes you'd like. If you'd still like me to make a few more changes could you give me a bit more detail?