code: def is_prime(number):
      
      if number < 2:
          return False
      if number % 2 == 0:
          return number == 2
  
      limit = int(math.sqrt(number))
      for divisor in range(3, limit + 1, 2):
          if number % divisor == 0:
              return False
  
      return True
docs: Testing given number to be a prime.
  
      >>> [n for n in range(100+1) if is_prime(n)]
      [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97]