code: def calculator(num1, operation, num2):
      if operation == "add":
          return num1 + num2
      elif operation == "subtract":
          return num1 - num2
      elif operation == "multiply":
          return num1 * num2
      elif operation == "divide":
          if num2 == 0:
              raise gr.Error("Cannot divide by zero!")
          return num1 / num2
  
label_desc: Use image node_id 1 for calling a global function with example usage: calculator(num1, operation, num2) and returns: unknown, unknown, unknown, unknown