input: Write a function to get the largest number in a list.
  assert getLargestNum([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])==10
  assert getLargestNum([10, 20, 45, 67, 84, 93])==93
  assert getLargestNum([5, 7, 9, 8, 6, 4, 3])==9
output: def getLargestNum(lst):
      return max(lst)