input: Write a python function to find the largest number in a list.
  assert get_largest_number([1, 2, 3, 4, 5]) == 5
  assert get_largest_number([10, 20, 30, 40, 50]) == 50
  assert get_largest_number([5, 1, 3, 9, 7]) == 9
output: def get_largest_number(lst):
      return max(lst)