input: Write a python function to find the largest number that can divide all elements in the array.
  assert maxDivisible([2, 4, 6, 8, 10]) == 2
  assert maxDivisible([3, 6, 9, 12, 15]) == 3
  assert maxDivisible([5, 10, 20, 25]) == 5
output: def maxDivisible(arr):
      from math import gcd
      from functools import reduce
      
      return reduce(gcd, arr)