how to see if a number is prime in python

1# Time Efficient Primality Check in Python
2
3def primeCheck(n):
4    # 0, 1, even numbers greater than 2 are NOT PRIME
5    if n==1 or n==0 or (n % 2 == 0 and n > 2):
6        return "Not prime"
7    else:
8        # Not prime if divisable by another number less
9        # or equal to the square root of itself.
10        # n**(1/2) returns square root of n
11        for i in range(3, int(n**(1/2))+1, 2):
12            if n%i == 0:
13                return "Not prime"
14        return "Prime"

1#make the function
2#to do this all hte vairibles go in side the function
3
4def CheckIfPrime ():
5    a1 = input("which number do you want to check")
6    a = int(a1)#you need the checking number as an int not an str
7    b = 2 #the number to check againts
8    c = ("yes")
9    while b < a:#run the loop
10        if a%b == 0:#check if the division has a remainder
11            c = ("no")#set the answer
12        b = b+1
13    print(c)#print the output
14CheckIfPrime ()#call the function  
15

1def is_prime(n: int) -> bool:
2    """Primality test using 6k+-1 optimization."""
3    if n <= 3:
4        return n > 1
5    if n % 2 == 0 or n % 3 == 0:
6        return False
7    i = 5
8    while i ** 2 <= n:
9        if n % i == 0 or n % (i + 2) == 0:
10            return False
11        i += 6
12    return True
13