Given a number n, what is the largest gap between successive
primes which are less than number n?
For example, if n = 12, the prime numbers less than 12 are: [2,
3, 5, 7, 11]. The largest gap between any two prime numbers in this
list is 4, so the function would return '4'.
>>>print(largestGap(12))
4
Write Python code to solve this problem, and include the
following 3 test cases in your answer.
>>>print(largestGap(100))
8
>>>print(largestGap(1000))
20
>>>print(largestGap(10000))
36...