Description: Write a function task\_4\_1 which takes no parameters. When called, prompt the user for an input with the string "Please enter your matriculation number:." First remove leading and trailing whitespaces. Then check if the input is an integer using the built-in functionality.
If the input is not a number, then output the following: "Invalid input. Not a number…"
If the input is a valid integer but is greater than (or equal to) 
12000000, output the following: "Invalid input. Not a valid matriculation number…"
Repeat asking the user to enter their matriculation number using the prompt above.
Once the user input a valid number, your function should return it (converted to an actual integer) 

My Problem is "If the input is a valid integer but is greater than (or equal to) 12000000, Output..." it's not working the way I wrote this condition, it creates an error that says "'>=' not supported between instances of 'str' and 'int'" and I dont know how to make it work the right way..

```py
import string
def task_4_1():
    num = input("Please enter your matriculation number: ")
    if(num.isdigit()):
        return(int(num.strip()))
    elif num>=12000000:
        print("Invalid input. Not a valid matriculation number...")
        num = input("Please enter your matriculation number: ")
    else:
       print("Invalid input. Not a valid matriculation number...")

```