Can anyone help please? (Python programming)

1-> Write a Python function that checks if positive integer n is a prime. Recall that n is a prime if it is divisible only by 1 and itself, hence not divisible by any integer in the range from 2 to sqrt(n), both inclusive.

2-> Write a prime number generator, using the above function. By default it should generate (infinitely) all primes. If given a value as argument, it should generate (infinitely) all primes larger than this value.

3-> Use your generator and a for loop to print the first 20 primes.