input: Write a python function to get the sum of all values in a nested dictionary.
  assert get_sum({"a":1, "b":2, "c":{"d":3, "e": 4}}) == 10
  assert get_sum({"x":5, "y":{"z":6, "w":7}, "v":8}) == 26
  assert get_sum({"m":{"n":9}, "o":10, "p":{"q":{"r":11}}}) == 30
output: def get_sum(d):
      total = 0
      for value in d.values():
          if isinstance(value, dict):
              total += get_sum(value)
          else:
              total += value
      return total