code: def prime3(a):
      if a < 2:
          return False
      if a == 2 or a == 3:
          return True  # manually test 2 and 3
      if a % 2 == 0 or a % 3 == 0:
          return False  # exclude multiples of 2 and 3
  
      maxDivisor = a**0.5
      d, i = 5, 2
      while d <= maxDivisor:
          if a % d == 0:
              return False
          d += i
          i = 6 - i  # this modifies 2 into 4 and viceversa
  
      return True
  
label_desc: Use image node_id 3 for calling a global function with example usage: prime3(a) and returns: True, False, True, False, False