code: def is_prime(n, mr_rounds=25):
      
      # as an optimization we quickly detect small primes using the list above
      if n <= first_primes[-1]:
          return n in first_primes
      # for small dividors (relatively frequent), euclidean division is best
      for p in first_primes:
          if n % p == 0:
              return False
      # the actual generic test; give a false prime with probability 2⁻⁵⁰
      return miller_rabin(n, mr_rounds)
docs: Test whether n is probably prime
  
      See <https://en.wikipedia.org/wiki/Primality_test#Probabilistic_tests>
  
      Arguments:
          n (int): the number to be tested
          mr_rounds (int, optional): number of Miller-Rabin iterations to run;
              defaults to 25 iterations, which is what the GMP library uses
  
      Returns:
          bool: when this function returns False, `n` is composite (not prime);
          when it returns True, `n` is prime with overwhelming probability