Is Number Prime?

Write a function the returns True or False, depending on whether the integer passed into it is a prime number.

Only numbers >1 can be prime numbers:

>>> is_prime(0)
False

>>> is_prime(1)
False

Any number >1 that has no divisors other than 1 and itself is a prime number:

>>> is_prime(2)
True

>>> is_prime(3)
True

>>> is_prime(4)
False

>>> is_prime(11)
True

>>> is_prime(999)
False

We’ve included a file, isprime.py, with a function, is_prime:

def is_prime(num):
    """Is a number a prime number?"""

However, this function is unimplemented.