find the next prime number in python

next_prime.py

#!/usr/bin/env python

def main():
    n = input('Find the next prime number greater great than: ')
    print find_next_prime(n+1)

def find_next_prime(n):
    return find_prime_in_range(n, 2*n)

def find_prime_in_range(a, b):
    for p in range(a, b):
        for i in range(2, p):
            if p % i == 0:
                break
        else:
            return p
    return None

if __name__ == '__main__':
    main()

Thanks a lot