input: Write a function to calculate the running total of numbers in a given list using numpy. The function should return an array with the cumulative sum of the input list. If the input list is empty, the function should return an empty list.
  assert runningTotal([1, 2, 3, 4, 5]).tolist()==[1, 3, 6, 10, 15]
  assert runningTotal([0, 1, 0, 1, 0]).tolist()==[0, 1, 1, 2, 2]
  assert runningTotal([-1, -1, -1, -1]).tolist()==[-1, -2, -3, -4]
  assert runningTotal([5]).tolist()==[5]
  assert runningTotal([]).tolist()==[]
output: import numpy as np
  
  def runningTotal(lst):
      if not lst:
          return np.array([])
      return np.cumsum(lst)