input: from typing import List
  
  def is_prime(numbers: List[int]) -> List[str]:
      """ Given a list of integers, determine for each number if it's prime or not.
      >>> is_prime([17, 22, 31, 44])
      ['17 is a prime number.', '22 is not a prime number.', '31 is a prime number.', '44 is not a prime number.']
      """
output:     results = []
      for num in numbers:
          if num > 1:
              for i in range(2, int(num**0.5) + 1):
                  if (num % i) == 0:
                      results.append(f"{num} is not a prime number.")
                      break
              else:
                  results.append(f"{num} is a prime number.")
          else:
              results.append(f"{num} is not a prime number.")
      return results