getting number and returning prime number in this order python code example

Example 1: python calculate prime numbers until numer

until = 20
[n for n in range(2, until) if all(n % m != 0 for m in range(2, n-1))]

Example 2: check if a number is prime python

n=input('Enter the number you want to check: ')
try:
    n=int(n)
except:
    print('Wrong input.')
    quit()
if n==1 or n==0:
    print('This is neither prime nor composite')
else:
    c=0
    for i in range(2,n):
        if n%i==0:
            c=c+1
    if c==0:
        print("This is a prime number")
    else:
        print('This  is a composite number.')