Bob too early

[GeF0rs]

I'm going through exercises in C# and exercise Bob opened too early.
There are tests that serve strings with only numbers, for example:
Assert.Equal("Whatever.", Bob.Response("1, 2, 3"));

And in order to determine that there is at least one letter character, you need to use either a linq or a loop
However, at the moment when this task opens, we know nothing about either one or the other.

I suggest either opening the exercise later or removing some of the tests.

[ErikSchierboom]

#2277 adds for-loops as a prerequisite.