how to insure a number is always prime in python code example

Example 1: prime number in python

def prime(num):
    if num>1:
        s=int(num/2)
        for i in range(2,s+1):
            if num%i==0:
                return("not prime")
                break
        return("prime")
print(prime(239))

Example 2: is_prime in python

# Program to check if a number is prime or not

#too take the input from user use "num: int = int(input('Give the value of num '))"
num: int = int(input('Give the value of Num: '))

# define a variable felix
felix = False

# prime numbers are greater than 1
if num > 1:
    # check for factors
    for i in range(2, num):
        if (num % i) == 0:
            # if factor is found, set flag to True
            felix = True
            # break out of loop
            break

# check if flag is True
if felix:
    print(num, "is not a prime number")
else:
    print(num, "is a prime number")