Put the following code in the Preloaded section:

with open("/home/codewarrior/solution.txt", "r") as file:
    f = file.read()
    
    import re
    forbidden = re.findall(r'|'.join(map(r"\b{}\b".format, [
    "**",
    "pow",
    "ipow",
    "open",
    "builtins",
    "__getattribute__",
    "eval",
    "exec",
    "globals"])), f)
    Test.assert_equals(forbidden, [], "Using forbidden commands")

I'm not sure if this will be sufficient, but it blocks the most obvious ways to raise n to the power of m and acts as an ok anticheat.

(You're asking in a wrong thread, it's feature requests, not content/site design)

By parsing the solution like this:

with open("/home/codewarrior/solution.txt", "r") as file:
    f = file.read()
    Test.assert_equals("**" in f, False, "You can't use '**'")

but this snippet will absolutely NOT suffice as an anticheat, and you'll have to ban other ways to raise a number to the power of n.

Apart from that, it's highly probable that you're working on a duplicate, so browse the katas before publishing anything.