Write primes_upto(n) returning all primes ≤ n using a list comprehension with all().
primes_upto(20) → [2, 3, 5, 7, 11, 13, 17, 19]
primes_upto(1) → []
Submit runs 4 tests, including hidden edge cases.
Each hint gives a little more help. Try on your own first.
Run your code to see the output here.