Escape indentation

[BashBedlam]

On line 15 you are callingis_prime_v1(n)a second time. Try it like this:

prime = []
def is_prime_v1(n):
     
    if n == 1:
     return False
     
    for d in range(2, n):
        if n % d == 0:
            return False
    prime.append(n)
    return n
   
for n in range(1,21):
  prime_number = is_prime_v1(n)
  if prime_number != False:
    print(prime_number)
    
print(prime)